HLSL: add subpass input types and methods

Add support for Subpass Input proposal of issue #1069.

Subpass input types are given as:

    layout(input_attachment_index = 1) SubpassInput<float4> subpass_f;
    layout(input_attachment_index = 2) SubpassInput<int4>   subpass_i;
    layout(input_attachment_index = 3) SubpassInput<uint4>  subpass_u;

    layout(input_attachment_index = 1) SubpassInputMS<float4> subpass_ms_f;
    layout(input_attachment_index = 2) SubpassInputMS<int4>   subpass_ms_i;
    layout(input_attachment_index = 3) SubpassInputMS<uint4>  subpass_ms_u;

The input attachment may also be specified using attribute syntax:

    [[vk::input_attachment_index(7)]] SubpassInput subpass_2;

The template type may be a shorter-than-vec4 vector, but currently user
structs are not supported.  (An unimplemented error will be issued).

The load operations are methods on objects of the above type:

    float4 result = subpass_f.SubpassLoad();
    int4   result = subpass_i.SubpassLoad();
    uint4  result = subpass_u.SubpassLoad();

    float4 result = subpass_ms_f.SubpassLoad(samp);
    int4   result = subpass_ms_i.SubpassLoad(samp);
    uint4  result = subpass_ms_u.SubpassLoad(samp);

Additionally, the AST printer could not print EOpSubpass* nodes.  Now it can.

Fixes #1069
diff --git a/Test/baseResults/hlsl.subpass.frag.out b/Test/baseResults/hlsl.subpass.frag.out
new file mode 100644
index 0000000..32db8fc
--- /dev/null
+++ b/Test/baseResults/hlsl.subpass.frag.out
@@ -0,0 +1,778 @@
+hlsl.subpass.frag
+Shader version: 500
+gl_FragCoord origin is upper left
+0:? Sequence
+0:68  Function Definition: @main( ( temp 4-component vector of float)
+0:68    Function Parameters: 
+0:?     Sequence
+0:69      Sequence
+0:69        move second child to first child ( temp 4-component vector of float)
+0:69          'result00' ( temp 4-component vector of float)
+0:69          subpassLoad ( temp 4-component vector of float)
+0:69            'subpass_f4' (layout( binding=1 input_attachment_index=1) uniform subpassInput)
+0:70      Sequence
+0:70        move second child to first child ( temp 4-component vector of int)
+0:70          'result01' ( temp 4-component vector of int)
+0:70          subpassLoad ( temp 4-component vector of int)
+0:70            'subpass_i4' ( uniform isubpassInput)
+0:71      Sequence
+0:71        move second child to first child ( temp 4-component vector of uint)
+0:71          'result02' ( temp 4-component vector of uint)
+0:71          subpassLoad ( temp 4-component vector of uint)
+0:71            'subpass_u4' ( uniform usubpassInput)
+0:73      Sequence
+0:73        move second child to first child ( temp 4-component vector of float)
+0:73          'result10' ( temp 4-component vector of float)
+0:73          subpassLoadMS ( temp 4-component vector of float)
+0:73            'subpass_ms_f4' ( uniform subpassInputMS)
+0:73            Constant:
+0:73              3 (const int)
+0:74      Sequence
+0:74        move second child to first child ( temp 4-component vector of int)
+0:74          'result11' ( temp 4-component vector of int)
+0:74          subpassLoadMS ( temp 4-component vector of int)
+0:74            'subpass_ms_i4' ( uniform isubpassInputMS)
+0:74            Constant:
+0:74              3 (const int)
+0:75      Sequence
+0:75        move second child to first child ( temp 4-component vector of uint)
+0:75          'result12' ( temp 4-component vector of uint)
+0:75          subpassLoadMS ( temp 4-component vector of uint)
+0:75            'subpass_ms_u4' ( uniform usubpassInputMS)
+0:75            Constant:
+0:75              3 (const int)
+0:77      Sequence
+0:77        move second child to first child ( temp 3-component vector of float)
+0:77          'result20' ( temp 3-component vector of float)
+0:77          Construct vec3 ( temp 3-component vector of float)
+0:77            subpassLoad ( temp 4-component vector of float)
+0:77              'subpass_f3' ( uniform subpassInput)
+0:78      Sequence
+0:78        move second child to first child ( temp 3-component vector of int)
+0:78          'result21' ( temp 3-component vector of int)
+0:78          Construct ivec3 ( temp 3-component vector of int)
+0:78            subpassLoad ( temp 4-component vector of int)
+0:78              'subpass_i3' ( uniform isubpassInput)
+0:79      Sequence
+0:79        move second child to first child ( temp 3-component vector of uint)
+0:79          'result22' ( temp 3-component vector of uint)
+0:79          Construct uvec3 ( temp 3-component vector of uint)
+0:79            subpassLoad ( temp 4-component vector of uint)
+0:79              'subpass_u3' ( uniform usubpassInput)
+0:81      Sequence
+0:81        move second child to first child ( temp 3-component vector of float)
+0:81          'result30' ( temp 3-component vector of float)
+0:81          Construct vec3 ( temp 3-component vector of float)
+0:81            subpassLoadMS ( temp 4-component vector of float)
+0:81              'subpass_ms_f3' ( uniform subpassInputMS)
+0:81              Constant:
+0:81                3 (const int)
+0:82      Sequence
+0:82        move second child to first child ( temp 3-component vector of int)
+0:82          'result31' ( temp 3-component vector of int)
+0:82          Construct ivec3 ( temp 3-component vector of int)
+0:82            subpassLoadMS ( temp 4-component vector of int)
+0:82              'subpass_ms_i3' ( uniform isubpassInputMS)
+0:82              Constant:
+0:82                3 (const int)
+0:83      Sequence
+0:83        move second child to first child ( temp 3-component vector of uint)
+0:83          'result32' ( temp 3-component vector of uint)
+0:83          Construct uvec3 ( temp 3-component vector of uint)
+0:83            subpassLoadMS ( temp 4-component vector of uint)
+0:83              'subpass_ms_u3' ( uniform usubpassInputMS)
+0:83              Constant:
+0:83                3 (const int)
+0:85      Sequence
+0:85        move second child to first child ( temp 2-component vector of float)
+0:85          'result40' ( temp 2-component vector of float)
+0:85          Construct vec2 ( temp 2-component vector of float)
+0:85            subpassLoad ( temp 4-component vector of float)
+0:85              'subpass_f2' ( uniform subpassInput)
+0:86      Sequence
+0:86        move second child to first child ( temp 2-component vector of int)
+0:86          'result41' ( temp 2-component vector of int)
+0:86          Construct ivec2 ( temp 2-component vector of int)
+0:86            subpassLoad ( temp 4-component vector of int)
+0:86              'subpass_i2' ( uniform isubpassInput)
+0:87      Sequence
+0:87        move second child to first child ( temp 2-component vector of uint)
+0:87          'result42' ( temp 2-component vector of uint)
+0:87          Construct uvec2 ( temp 2-component vector of uint)
+0:87            subpassLoad ( temp 4-component vector of uint)
+0:87              'subpass_u2' ( uniform usubpassInput)
+0:89      Sequence
+0:89        move second child to first child ( temp 2-component vector of float)
+0:89          'result50' ( temp 2-component vector of float)
+0:89          Construct vec2 ( temp 2-component vector of float)
+0:89            subpassLoadMS ( temp 4-component vector of float)
+0:89              'subpass_ms_f2' ( uniform subpassInputMS)
+0:89              Constant:
+0:89                2 (const int)
+0:90      Sequence
+0:90        move second child to first child ( temp 2-component vector of int)
+0:90          'result51' ( temp 2-component vector of int)
+0:90          Construct ivec2 ( temp 2-component vector of int)
+0:90            subpassLoadMS ( temp 4-component vector of int)
+0:90              'subpass_ms_i2' ( uniform isubpassInputMS)
+0:90              Constant:
+0:90                2 (const int)
+0:91      Sequence
+0:91        move second child to first child ( temp 2-component vector of uint)
+0:91          'result52' ( temp 2-component vector of uint)
+0:91          Construct uvec2 ( temp 2-component vector of uint)
+0:91            subpassLoadMS ( temp 4-component vector of uint)
+0:91              'subpass_ms_u2' ( uniform usubpassInputMS)
+0:91              Constant:
+0:91                2 (const int)
+0:93      Sequence
+0:93        move second child to first child ( temp float)
+0:93          'result60' ( temp float)
+0:93          Construct float ( temp float)
+0:93            subpassLoad ( temp 4-component vector of float)
+0:93              'subpass_f' ( uniform subpassInput)
+0:94      Sequence
+0:94        move second child to first child ( temp int)
+0:94          'result61' ( temp int)
+0:94          Construct int ( temp int)
+0:94            subpassLoad ( temp 4-component vector of int)
+0:94              'subpass_i' ( uniform isubpassInput)
+0:95      Sequence
+0:95        move second child to first child ( temp uint)
+0:95          'result62' ( temp uint)
+0:95          Construct uint ( temp uint)
+0:95            subpassLoad ( temp 4-component vector of uint)
+0:95              'subpass_u' ( uniform usubpassInput)
+0:97      Sequence
+0:97        move second child to first child ( temp float)
+0:97          'result70' ( temp float)
+0:97          Construct float ( temp float)
+0:97            subpassLoadMS ( temp 4-component vector of float)
+0:97              'subpass_ms_f' ( uniform subpassInputMS)
+0:97              Constant:
+0:97                2 (const int)
+0:98      Sequence
+0:98        move second child to first child ( temp int)
+0:98          'result71' ( temp int)
+0:98          Construct int ( temp int)
+0:98            subpassLoadMS ( temp 4-component vector of int)
+0:98              'subpass_ms_i' ( uniform isubpassInputMS)
+0:98              Constant:
+0:98                2 (const int)
+0:99      Sequence
+0:99        move second child to first child ( temp uint)
+0:99          'result72' ( temp uint)
+0:99          Construct uint ( temp uint)
+0:99            subpassLoadMS ( temp 4-component vector of uint)
+0:99              'subpass_ms_u' ( uniform usubpassInputMS)
+0:99              Constant:
+0:99                2 (const int)
+0:101      Sequence
+0:101        move second child to first child ( temp 4-component vector of float)
+0:101          'result73' ( temp 4-component vector of float)
+0:101          subpassLoad ( temp 4-component vector of float)
+0:101            'subpass_2' ( uniform subpassInput)
+0:112      Branch: Return with expression
+0:112        Constant:
+0:112          0.000000
+0:112          0.000000
+0:112          0.000000
+0:112          0.000000
+0:68  Function Definition: main( ( temp void)
+0:68    Function Parameters: 
+0:?     Sequence
+0:68      move second child to first child ( temp 4-component vector of float)
+0:?         '@entryPointOutput' (layout( location=0) out 4-component vector of float)
+0:68        Function Call: @main( ( temp 4-component vector of float)
+0:?   Linker Objects
+0:?     'subpass_f4' (layout( binding=1 input_attachment_index=1) uniform subpassInput)
+0:?     'subpass_i4' ( uniform isubpassInput)
+0:?     'subpass_u4' ( uniform usubpassInput)
+0:?     'subpass_ms_f4' ( uniform subpassInputMS)
+0:?     'subpass_ms_i4' ( uniform isubpassInputMS)
+0:?     'subpass_ms_u4' ( uniform usubpassInputMS)
+0:?     'subpass_f3' ( uniform subpassInput)
+0:?     'subpass_i3' ( uniform isubpassInput)
+0:?     'subpass_u3' ( uniform usubpassInput)
+0:?     'subpass_ms_f3' ( uniform subpassInputMS)
+0:?     'subpass_ms_i3' ( uniform isubpassInputMS)
+0:?     'subpass_ms_u3' ( uniform usubpassInputMS)
+0:?     'subpass_f2' ( uniform subpassInput)
+0:?     'subpass_i2' ( uniform isubpassInput)
+0:?     'subpass_u2' ( uniform usubpassInput)
+0:?     'subpass_ms_f2' ( uniform subpassInputMS)
+0:?     'subpass_ms_i2' ( uniform isubpassInputMS)
+0:?     'subpass_ms_u2' ( uniform usubpassInputMS)
+0:?     'subpass_f' ( uniform subpassInput)
+0:?     'subpass_i' ( uniform isubpassInput)
+0:?     'subpass_u' ( uniform usubpassInput)
+0:?     'subpass_ms_f' ( uniform subpassInputMS)
+0:?     'subpass_ms_i' ( uniform isubpassInputMS)
+0:?     'subpass_ms_u' ( uniform usubpassInputMS)
+0:?     'subpass_2' ( uniform subpassInput)
+0:?     '@entryPointOutput' (layout( location=0) out 4-component vector of float)
+
+
+Linked fragment stage:
+
+
+Shader version: 500
+gl_FragCoord origin is upper left
+0:? Sequence
+0:68  Function Definition: @main( ( temp 4-component vector of float)
+0:68    Function Parameters: 
+0:?     Sequence
+0:69      Sequence
+0:69        move second child to first child ( temp 4-component vector of float)
+0:69          'result00' ( temp 4-component vector of float)
+0:69          subpassLoad ( temp 4-component vector of float)
+0:69            'subpass_f4' (layout( binding=1 input_attachment_index=1) uniform subpassInput)
+0:70      Sequence
+0:70        move second child to first child ( temp 4-component vector of int)
+0:70          'result01' ( temp 4-component vector of int)
+0:70          subpassLoad ( temp 4-component vector of int)
+0:70            'subpass_i4' ( uniform isubpassInput)
+0:71      Sequence
+0:71        move second child to first child ( temp 4-component vector of uint)
+0:71          'result02' ( temp 4-component vector of uint)
+0:71          subpassLoad ( temp 4-component vector of uint)
+0:71            'subpass_u4' ( uniform usubpassInput)
+0:73      Sequence
+0:73        move second child to first child ( temp 4-component vector of float)
+0:73          'result10' ( temp 4-component vector of float)
+0:73          subpassLoadMS ( temp 4-component vector of float)
+0:73            'subpass_ms_f4' ( uniform subpassInputMS)
+0:73            Constant:
+0:73              3 (const int)
+0:74      Sequence
+0:74        move second child to first child ( temp 4-component vector of int)
+0:74          'result11' ( temp 4-component vector of int)
+0:74          subpassLoadMS ( temp 4-component vector of int)
+0:74            'subpass_ms_i4' ( uniform isubpassInputMS)
+0:74            Constant:
+0:74              3 (const int)
+0:75      Sequence
+0:75        move second child to first child ( temp 4-component vector of uint)
+0:75          'result12' ( temp 4-component vector of uint)
+0:75          subpassLoadMS ( temp 4-component vector of uint)
+0:75            'subpass_ms_u4' ( uniform usubpassInputMS)
+0:75            Constant:
+0:75              3 (const int)
+0:77      Sequence
+0:77        move second child to first child ( temp 3-component vector of float)
+0:77          'result20' ( temp 3-component vector of float)
+0:77          Construct vec3 ( temp 3-component vector of float)
+0:77            subpassLoad ( temp 4-component vector of float)
+0:77              'subpass_f3' ( uniform subpassInput)
+0:78      Sequence
+0:78        move second child to first child ( temp 3-component vector of int)
+0:78          'result21' ( temp 3-component vector of int)
+0:78          Construct ivec3 ( temp 3-component vector of int)
+0:78            subpassLoad ( temp 4-component vector of int)
+0:78              'subpass_i3' ( uniform isubpassInput)
+0:79      Sequence
+0:79        move second child to first child ( temp 3-component vector of uint)
+0:79          'result22' ( temp 3-component vector of uint)
+0:79          Construct uvec3 ( temp 3-component vector of uint)
+0:79            subpassLoad ( temp 4-component vector of uint)
+0:79              'subpass_u3' ( uniform usubpassInput)
+0:81      Sequence
+0:81        move second child to first child ( temp 3-component vector of float)
+0:81          'result30' ( temp 3-component vector of float)
+0:81          Construct vec3 ( temp 3-component vector of float)
+0:81            subpassLoadMS ( temp 4-component vector of float)
+0:81              'subpass_ms_f3' ( uniform subpassInputMS)
+0:81              Constant:
+0:81                3 (const int)
+0:82      Sequence
+0:82        move second child to first child ( temp 3-component vector of int)
+0:82          'result31' ( temp 3-component vector of int)
+0:82          Construct ivec3 ( temp 3-component vector of int)
+0:82            subpassLoadMS ( temp 4-component vector of int)
+0:82              'subpass_ms_i3' ( uniform isubpassInputMS)
+0:82              Constant:
+0:82                3 (const int)
+0:83      Sequence
+0:83        move second child to first child ( temp 3-component vector of uint)
+0:83          'result32' ( temp 3-component vector of uint)
+0:83          Construct uvec3 ( temp 3-component vector of uint)
+0:83            subpassLoadMS ( temp 4-component vector of uint)
+0:83              'subpass_ms_u3' ( uniform usubpassInputMS)
+0:83              Constant:
+0:83                3 (const int)
+0:85      Sequence
+0:85        move second child to first child ( temp 2-component vector of float)
+0:85          'result40' ( temp 2-component vector of float)
+0:85          Construct vec2 ( temp 2-component vector of float)
+0:85            subpassLoad ( temp 4-component vector of float)
+0:85              'subpass_f2' ( uniform subpassInput)
+0:86      Sequence
+0:86        move second child to first child ( temp 2-component vector of int)
+0:86          'result41' ( temp 2-component vector of int)
+0:86          Construct ivec2 ( temp 2-component vector of int)
+0:86            subpassLoad ( temp 4-component vector of int)
+0:86              'subpass_i2' ( uniform isubpassInput)
+0:87      Sequence
+0:87        move second child to first child ( temp 2-component vector of uint)
+0:87          'result42' ( temp 2-component vector of uint)
+0:87          Construct uvec2 ( temp 2-component vector of uint)
+0:87            subpassLoad ( temp 4-component vector of uint)
+0:87              'subpass_u2' ( uniform usubpassInput)
+0:89      Sequence
+0:89        move second child to first child ( temp 2-component vector of float)
+0:89          'result50' ( temp 2-component vector of float)
+0:89          Construct vec2 ( temp 2-component vector of float)
+0:89            subpassLoadMS ( temp 4-component vector of float)
+0:89              'subpass_ms_f2' ( uniform subpassInputMS)
+0:89              Constant:
+0:89                2 (const int)
+0:90      Sequence
+0:90        move second child to first child ( temp 2-component vector of int)
+0:90          'result51' ( temp 2-component vector of int)
+0:90          Construct ivec2 ( temp 2-component vector of int)
+0:90            subpassLoadMS ( temp 4-component vector of int)
+0:90              'subpass_ms_i2' ( uniform isubpassInputMS)
+0:90              Constant:
+0:90                2 (const int)
+0:91      Sequence
+0:91        move second child to first child ( temp 2-component vector of uint)
+0:91          'result52' ( temp 2-component vector of uint)
+0:91          Construct uvec2 ( temp 2-component vector of uint)
+0:91            subpassLoadMS ( temp 4-component vector of uint)
+0:91              'subpass_ms_u2' ( uniform usubpassInputMS)
+0:91              Constant:
+0:91                2 (const int)
+0:93      Sequence
+0:93        move second child to first child ( temp float)
+0:93          'result60' ( temp float)
+0:93          Construct float ( temp float)
+0:93            subpassLoad ( temp 4-component vector of float)
+0:93              'subpass_f' ( uniform subpassInput)
+0:94      Sequence
+0:94        move second child to first child ( temp int)
+0:94          'result61' ( temp int)
+0:94          Construct int ( temp int)
+0:94            subpassLoad ( temp 4-component vector of int)
+0:94              'subpass_i' ( uniform isubpassInput)
+0:95      Sequence
+0:95        move second child to first child ( temp uint)
+0:95          'result62' ( temp uint)
+0:95          Construct uint ( temp uint)
+0:95            subpassLoad ( temp 4-component vector of uint)
+0:95              'subpass_u' ( uniform usubpassInput)
+0:97      Sequence
+0:97        move second child to first child ( temp float)
+0:97          'result70' ( temp float)
+0:97          Construct float ( temp float)
+0:97            subpassLoadMS ( temp 4-component vector of float)
+0:97              'subpass_ms_f' ( uniform subpassInputMS)
+0:97              Constant:
+0:97                2 (const int)
+0:98      Sequence
+0:98        move second child to first child ( temp int)
+0:98          'result71' ( temp int)
+0:98          Construct int ( temp int)
+0:98            subpassLoadMS ( temp 4-component vector of int)
+0:98              'subpass_ms_i' ( uniform isubpassInputMS)
+0:98              Constant:
+0:98                2 (const int)
+0:99      Sequence
+0:99        move second child to first child ( temp uint)
+0:99          'result72' ( temp uint)
+0:99          Construct uint ( temp uint)
+0:99            subpassLoadMS ( temp 4-component vector of uint)
+0:99              'subpass_ms_u' ( uniform usubpassInputMS)
+0:99              Constant:
+0:99                2 (const int)
+0:101      Sequence
+0:101        move second child to first child ( temp 4-component vector of float)
+0:101          'result73' ( temp 4-component vector of float)
+0:101          subpassLoad ( temp 4-component vector of float)
+0:101            'subpass_2' ( uniform subpassInput)
+0:112      Branch: Return with expression
+0:112        Constant:
+0:112          0.000000
+0:112          0.000000
+0:112          0.000000
+0:112          0.000000
+0:68  Function Definition: main( ( temp void)
+0:68    Function Parameters: 
+0:?     Sequence
+0:68      move second child to first child ( temp 4-component vector of float)
+0:?         '@entryPointOutput' (layout( location=0) out 4-component vector of float)
+0:68        Function Call: @main( ( temp 4-component vector of float)
+0:?   Linker Objects
+0:?     'subpass_f4' (layout( binding=1 input_attachment_index=1) uniform subpassInput)
+0:?     'subpass_i4' ( uniform isubpassInput)
+0:?     'subpass_u4' ( uniform usubpassInput)
+0:?     'subpass_ms_f4' ( uniform subpassInputMS)
+0:?     'subpass_ms_i4' ( uniform isubpassInputMS)
+0:?     'subpass_ms_u4' ( uniform usubpassInputMS)
+0:?     'subpass_f3' ( uniform subpassInput)
+0:?     'subpass_i3' ( uniform isubpassInput)
+0:?     'subpass_u3' ( uniform usubpassInput)
+0:?     'subpass_ms_f3' ( uniform subpassInputMS)
+0:?     'subpass_ms_i3' ( uniform isubpassInputMS)
+0:?     'subpass_ms_u3' ( uniform usubpassInputMS)
+0:?     'subpass_f2' ( uniform subpassInput)
+0:?     'subpass_i2' ( uniform isubpassInput)
+0:?     'subpass_u2' ( uniform usubpassInput)
+0:?     'subpass_ms_f2' ( uniform subpassInputMS)
+0:?     'subpass_ms_i2' ( uniform isubpassInputMS)
+0:?     'subpass_ms_u2' ( uniform usubpassInputMS)
+0:?     'subpass_f' ( uniform subpassInput)
+0:?     'subpass_i' ( uniform isubpassInput)
+0:?     'subpass_u' ( uniform usubpassInput)
+0:?     'subpass_ms_f' ( uniform subpassInputMS)
+0:?     'subpass_ms_i' ( uniform isubpassInputMS)
+0:?     'subpass_ms_u' ( uniform usubpassInputMS)
+0:?     'subpass_2' ( uniform subpassInput)
+0:?     '@entryPointOutput' (layout( location=0) out 4-component vector of float)
+
+// Module Version 10000
+// Generated by (magic number): 80001
+// Id's are bound by 204
+
+                              Capability Shader
+                              Capability StorageImageMultisample
+                              Capability InputAttachment
+               1:             ExtInstImport  "GLSL.std.450"
+                              MemoryModel Logical GLSL450
+                              EntryPoint Fragment 4  "main" 202
+                              ExecutionMode 4 OriginUpperLeft
+                              Source HLSL 500
+                              Name 4  "main"
+                              Name 9  "@main("
+                              Name 12  "result00"
+                              Name 15  "subpass_f4"
+                              Name 24  "result01"
+                              Name 27  "subpass_i4"
+                              Name 33  "result02"
+                              Name 36  "subpass_u4"
+                              Name 39  "result10"
+                              Name 42  "subpass_ms_f4"
+                              Name 46  "result11"
+                              Name 49  "subpass_ms_i4"
+                              Name 52  "result12"
+                              Name 55  "subpass_ms_u4"
+                              Name 60  "result20"
+                              Name 61  "subpass_f3"
+                              Name 70  "result21"
+                              Name 71  "subpass_i3"
+                              Name 80  "result22"
+                              Name 81  "subpass_u3"
+                              Name 88  "result30"
+                              Name 89  "subpass_ms_f3"
+                              Name 96  "result31"
+                              Name 97  "subpass_ms_i3"
+                              Name 104  "result32"
+                              Name 105  "subpass_ms_u3"
+                              Name 114  "result40"
+                              Name 115  "subpass_f2"
+                              Name 122  "result41"
+                              Name 123  "subpass_i2"
+                              Name 131  "result42"
+                              Name 132  "subpass_u2"
+                              Name 138  "result50"
+                              Name 139  "subpass_ms_f2"
+                              Name 146  "result51"
+                              Name 147  "subpass_ms_i2"
+                              Name 153  "result52"
+                              Name 154  "subpass_ms_u2"
+                              Name 161  "result60"
+                              Name 162  "subpass_f"
+                              Name 167  "result61"
+                              Name 168  "subpass_i"
+                              Name 173  "result62"
+                              Name 174  "subpass_u"
+                              Name 178  "result70"
+                              Name 179  "subpass_ms_f"
+                              Name 183  "result71"
+                              Name 184  "subpass_ms_i"
+                              Name 188  "result72"
+                              Name 189  "subpass_ms_u"
+                              Name 193  "result73"
+                              Name 194  "subpass_2"
+                              Name 202  "@entryPointOutput"
+                              Decorate 15(subpass_f4) DescriptorSet 0
+                              Decorate 15(subpass_f4) Binding 1
+                              Decorate 15(subpass_f4) InputAttachmentIndex 1
+                              Decorate 27(subpass_i4) DescriptorSet 0
+                              Decorate 27(subpass_i4) InputAttachmentIndex 2
+                              Decorate 36(subpass_u4) DescriptorSet 0
+                              Decorate 36(subpass_u4) InputAttachmentIndex 3
+                              Decorate 42(subpass_ms_f4) DescriptorSet 0
+                              Decorate 42(subpass_ms_f4) InputAttachmentIndex 4
+                              Decorate 49(subpass_ms_i4) DescriptorSet 0
+                              Decorate 49(subpass_ms_i4) InputAttachmentIndex 5
+                              Decorate 55(subpass_ms_u4) DescriptorSet 0
+                              Decorate 55(subpass_ms_u4) InputAttachmentIndex 6
+                              Decorate 61(subpass_f3) DescriptorSet 0
+                              Decorate 61(subpass_f3) InputAttachmentIndex 1
+                              Decorate 71(subpass_i3) DescriptorSet 0
+                              Decorate 71(subpass_i3) InputAttachmentIndex 2
+                              Decorate 81(subpass_u3) DescriptorSet 0
+                              Decorate 81(subpass_u3) InputAttachmentIndex 3
+                              Decorate 89(subpass_ms_f3) DescriptorSet 0
+                              Decorate 89(subpass_ms_f3) InputAttachmentIndex 4
+                              Decorate 97(subpass_ms_i3) DescriptorSet 0
+                              Decorate 97(subpass_ms_i3) InputAttachmentIndex 5
+                              Decorate 105(subpass_ms_u3) DescriptorSet 0
+                              Decorate 105(subpass_ms_u3) InputAttachmentIndex 6
+                              Decorate 115(subpass_f2) DescriptorSet 0
+                              Decorate 115(subpass_f2) InputAttachmentIndex 1
+                              Decorate 123(subpass_i2) DescriptorSet 0
+                              Decorate 123(subpass_i2) InputAttachmentIndex 2
+                              Decorate 132(subpass_u2) DescriptorSet 0
+                              Decorate 132(subpass_u2) InputAttachmentIndex 3
+                              Decorate 139(subpass_ms_f2) DescriptorSet 0
+                              Decorate 139(subpass_ms_f2) InputAttachmentIndex 4
+                              Decorate 147(subpass_ms_i2) DescriptorSet 0
+                              Decorate 147(subpass_ms_i2) InputAttachmentIndex 5
+                              Decorate 154(subpass_ms_u2) DescriptorSet 0
+                              Decorate 154(subpass_ms_u2) InputAttachmentIndex 6
+                              Decorate 162(subpass_f) DescriptorSet 0
+                              Decorate 162(subpass_f) InputAttachmentIndex 1
+                              Decorate 168(subpass_i) DescriptorSet 0
+                              Decorate 168(subpass_i) InputAttachmentIndex 2
+                              Decorate 174(subpass_u) DescriptorSet 0
+                              Decorate 174(subpass_u) InputAttachmentIndex 3
+                              Decorate 179(subpass_ms_f) DescriptorSet 0
+                              Decorate 179(subpass_ms_f) InputAttachmentIndex 4
+                              Decorate 184(subpass_ms_i) DescriptorSet 0
+                              Decorate 184(subpass_ms_i) InputAttachmentIndex 5
+                              Decorate 189(subpass_ms_u) DescriptorSet 0
+                              Decorate 189(subpass_ms_u) InputAttachmentIndex 6
+                              Decorate 194(subpass_2) DescriptorSet 0
+                              Decorate 194(subpass_2) InputAttachmentIndex 7
+                              Decorate 202(@entryPointOutput) Location 0
+               2:             TypeVoid
+               3:             TypeFunction 2
+               6:             TypeFloat 32
+               7:             TypeVector 6(float) 4
+               8:             TypeFunction 7(fvec4)
+              11:             TypePointer Function 7(fvec4)
+              13:             TypeImage 6(float) SubpassData nonsampled format:Unknown
+              14:             TypePointer UniformConstant 13
+  15(subpass_f4):     14(ptr) Variable UniformConstant
+              17:             TypeInt 32 1
+              18:     17(int) Constant 0
+              19:             TypeVector 17(int) 2
+              20:   19(ivec2) ConstantComposite 18 18
+              22:             TypeVector 17(int) 4
+              23:             TypePointer Function 22(ivec4)
+              25:             TypeImage 17(int) SubpassData nonsampled format:Unknown
+              26:             TypePointer UniformConstant 25
+  27(subpass_i4):     26(ptr) Variable UniformConstant
+              30:             TypeInt 32 0
+              31:             TypeVector 30(int) 4
+              32:             TypePointer Function 31(ivec4)
+              34:             TypeImage 30(int) SubpassData nonsampled format:Unknown
+              35:             TypePointer UniformConstant 34
+  36(subpass_u4):     35(ptr) Variable UniformConstant
+              40:             TypeImage 6(float) SubpassData multi-sampled nonsampled format:Unknown
+              41:             TypePointer UniformConstant 40
+42(subpass_ms_f4):     41(ptr) Variable UniformConstant
+              44:     17(int) Constant 3
+              47:             TypeImage 17(int) SubpassData multi-sampled nonsampled format:Unknown
+              48:             TypePointer UniformConstant 47
+49(subpass_ms_i4):     48(ptr) Variable UniformConstant
+              53:             TypeImage 30(int) SubpassData multi-sampled nonsampled format:Unknown
+              54:             TypePointer UniformConstant 53
+55(subpass_ms_u4):     54(ptr) Variable UniformConstant
+              58:             TypeVector 6(float) 3
+              59:             TypePointer Function 58(fvec3)
+  61(subpass_f3):     14(ptr) Variable UniformConstant
+              68:             TypeVector 17(int) 3
+              69:             TypePointer Function 68(ivec3)
+  71(subpass_i3):     26(ptr) Variable UniformConstant
+              78:             TypeVector 30(int) 3
+              79:             TypePointer Function 78(ivec3)
+  81(subpass_u3):     35(ptr) Variable UniformConstant
+89(subpass_ms_f3):     41(ptr) Variable UniformConstant
+97(subpass_ms_i3):     48(ptr) Variable UniformConstant
+105(subpass_ms_u3):     54(ptr) Variable UniformConstant
+             112:             TypeVector 6(float) 2
+             113:             TypePointer Function 112(fvec2)
+ 115(subpass_f2):     14(ptr) Variable UniformConstant
+             121:             TypePointer Function 19(ivec2)
+ 123(subpass_i2):     26(ptr) Variable UniformConstant
+             129:             TypeVector 30(int) 2
+             130:             TypePointer Function 129(ivec2)
+ 132(subpass_u2):     35(ptr) Variable UniformConstant
+139(subpass_ms_f2):     41(ptr) Variable UniformConstant
+             141:     17(int) Constant 2
+147(subpass_ms_i2):     48(ptr) Variable UniformConstant
+154(subpass_ms_u2):     54(ptr) Variable UniformConstant
+             160:             TypePointer Function 6(float)
+  162(subpass_f):     14(ptr) Variable UniformConstant
+             166:             TypePointer Function 17(int)
+  168(subpass_i):     26(ptr) Variable UniformConstant
+             172:             TypePointer Function 30(int)
+  174(subpass_u):     35(ptr) Variable UniformConstant
+179(subpass_ms_f):     41(ptr) Variable UniformConstant
+184(subpass_ms_i):     48(ptr) Variable UniformConstant
+189(subpass_ms_u):     54(ptr) Variable UniformConstant
+  194(subpass_2):     14(ptr) Variable UniformConstant
+             197:    6(float) Constant 0
+             198:    7(fvec4) ConstantComposite 197 197 197 197
+             201:             TypePointer Output 7(fvec4)
+202(@entryPointOutput):    201(ptr) Variable Output
+         4(main):           2 Function None 3
+               5:             Label
+             203:    7(fvec4) FunctionCall 9(@main()
+                              Store 202(@entryPointOutput) 203
+                              Return
+                              FunctionEnd
+       9(@main():    7(fvec4) Function None 8
+              10:             Label
+    12(result00):     11(ptr) Variable Function
+    24(result01):     23(ptr) Variable Function
+    33(result02):     32(ptr) Variable Function
+    39(result10):     11(ptr) Variable Function
+    46(result11):     23(ptr) Variable Function
+    52(result12):     32(ptr) Variable Function
+    60(result20):     59(ptr) Variable Function
+    70(result21):     69(ptr) Variable Function
+    80(result22):     79(ptr) Variable Function
+    88(result30):     59(ptr) Variable Function
+    96(result31):     69(ptr) Variable Function
+   104(result32):     79(ptr) Variable Function
+   114(result40):    113(ptr) Variable Function
+   122(result41):    121(ptr) Variable Function
+   131(result42):    130(ptr) Variable Function
+   138(result50):    113(ptr) Variable Function
+   146(result51):    121(ptr) Variable Function
+   153(result52):    130(ptr) Variable Function
+   161(result60):    160(ptr) Variable Function
+   167(result61):    166(ptr) Variable Function
+   173(result62):    172(ptr) Variable Function
+   178(result70):    160(ptr) Variable Function
+   183(result71):    166(ptr) Variable Function
+   188(result72):    172(ptr) Variable Function
+   193(result73):     11(ptr) Variable Function
+              16:          13 Load 15(subpass_f4)
+              21:    7(fvec4) ImageRead 16 20
+                              Store 12(result00) 21
+              28:          25 Load 27(subpass_i4)
+              29:   22(ivec4) ImageRead 28 20
+                              Store 24(result01) 29
+              37:          34 Load 36(subpass_u4)
+              38:   31(ivec4) ImageRead 37 20
+                              Store 33(result02) 38
+              43:          40 Load 42(subpass_ms_f4)
+              45:    7(fvec4) ImageRead 43 20 Sample 44
+                              Store 39(result10) 45
+              50:          47 Load 49(subpass_ms_i4)
+              51:   22(ivec4) ImageRead 50 20 Sample 44
+                              Store 46(result11) 51
+              56:          53 Load 55(subpass_ms_u4)
+              57:   31(ivec4) ImageRead 56 20 Sample 44
+                              Store 52(result12) 57
+              62:          13 Load 61(subpass_f3)
+              63:    7(fvec4) ImageRead 62 20
+              64:    6(float) CompositeExtract 63 0
+              65:    6(float) CompositeExtract 63 1
+              66:    6(float) CompositeExtract 63 2
+              67:   58(fvec3) CompositeConstruct 64 65 66
+                              Store 60(result20) 67
+              72:          25 Load 71(subpass_i3)
+              73:   22(ivec4) ImageRead 72 20
+              74:     17(int) CompositeExtract 73 0
+              75:     17(int) CompositeExtract 73 1
+              76:     17(int) CompositeExtract 73 2
+              77:   68(ivec3) CompositeConstruct 74 75 76
+                              Store 70(result21) 77
+              82:          34 Load 81(subpass_u3)
+              83:   31(ivec4) ImageRead 82 20
+              84:     30(int) CompositeExtract 83 0
+              85:     30(int) CompositeExtract 83 1
+              86:     30(int) CompositeExtract 83 2
+              87:   78(ivec3) CompositeConstruct 84 85 86
+                              Store 80(result22) 87
+              90:          40 Load 89(subpass_ms_f3)
+              91:    7(fvec4) ImageRead 90 20 Sample 44
+              92:    6(float) CompositeExtract 91 0
+              93:    6(float) CompositeExtract 91 1
+              94:    6(float) CompositeExtract 91 2
+              95:   58(fvec3) CompositeConstruct 92 93 94
+                              Store 88(result30) 95
+              98:          47 Load 97(subpass_ms_i3)
+              99:   22(ivec4) ImageRead 98 20 Sample 44
+             100:     17(int) CompositeExtract 99 0
+             101:     17(int) CompositeExtract 99 1
+             102:     17(int) CompositeExtract 99 2
+             103:   68(ivec3) CompositeConstruct 100 101 102
+                              Store 96(result31) 103
+             106:          53 Load 105(subpass_ms_u3)
+             107:   31(ivec4) ImageRead 106 20 Sample 44
+             108:     30(int) CompositeExtract 107 0
+             109:     30(int) CompositeExtract 107 1
+             110:     30(int) CompositeExtract 107 2
+             111:   78(ivec3) CompositeConstruct 108 109 110
+                              Store 104(result32) 111
+             116:          13 Load 115(subpass_f2)
+             117:    7(fvec4) ImageRead 116 20
+             118:    6(float) CompositeExtract 117 0
+             119:    6(float) CompositeExtract 117 1
+             120:  112(fvec2) CompositeConstruct 118 119
+                              Store 114(result40) 120
+             124:          25 Load 123(subpass_i2)
+             125:   22(ivec4) ImageRead 124 20
+             126:     17(int) CompositeExtract 125 0
+             127:     17(int) CompositeExtract 125 1
+             128:   19(ivec2) CompositeConstruct 126 127
+                              Store 122(result41) 128
+             133:          34 Load 132(subpass_u2)
+             134:   31(ivec4) ImageRead 133 20
+             135:     30(int) CompositeExtract 134 0
+             136:     30(int) CompositeExtract 134 1
+             137:  129(ivec2) CompositeConstruct 135 136
+                              Store 131(result42) 137
+             140:          40 Load 139(subpass_ms_f2)
+             142:    7(fvec4) ImageRead 140 20 Sample 141
+             143:    6(float) CompositeExtract 142 0
+             144:    6(float) CompositeExtract 142 1
+             145:  112(fvec2) CompositeConstruct 143 144
+                              Store 138(result50) 145
+             148:          47 Load 147(subpass_ms_i2)
+             149:   22(ivec4) ImageRead 148 20 Sample 141
+             150:     17(int) CompositeExtract 149 0
+             151:     17(int) CompositeExtract 149 1
+             152:   19(ivec2) CompositeConstruct 150 151
+                              Store 146(result51) 152
+             155:          53 Load 154(subpass_ms_u2)
+             156:   31(ivec4) ImageRead 155 20 Sample 141
+             157:     30(int) CompositeExtract 156 0
+             158:     30(int) CompositeExtract 156 1
+             159:  129(ivec2) CompositeConstruct 157 158
+                              Store 153(result52) 159
+             163:          13 Load 162(subpass_f)
+             164:    7(fvec4) ImageRead 163 20
+             165:    6(float) CompositeExtract 164 0
+                              Store 161(result60) 165
+             169:          25 Load 168(subpass_i)
+             170:   22(ivec4) ImageRead 169 20
+             171:     17(int) CompositeExtract 170 0
+                              Store 167(result61) 171
+             175:          34 Load 174(subpass_u)
+             176:   31(ivec4) ImageRead 175 20
+             177:     30(int) CompositeExtract 176 0
+                              Store 173(result62) 177
+             180:          40 Load 179(subpass_ms_f)
+             181:    7(fvec4) ImageRead 180 20 Sample 141
+             182:    6(float) CompositeExtract 181 0
+                              Store 178(result70) 182
+             185:          47 Load 184(subpass_ms_i)
+             186:   22(ivec4) ImageRead 185 20 Sample 141
+             187:     17(int) CompositeExtract 186 0
+                              Store 183(result71) 187
+             190:          53 Load 189(subpass_ms_u)
+             191:   31(ivec4) ImageRead 190 20 Sample 141
+             192:     30(int) CompositeExtract 191 0
+                              Store 188(result72) 192
+             195:          13 Load 194(subpass_2)
+             196:    7(fvec4) ImageRead 195 20
+                              Store 193(result73) 196
+                              ReturnValue 198
+                              FunctionEnd
diff --git a/Test/baseResults/spv.register.subpass.frag.out b/Test/baseResults/spv.register.subpass.frag.out
new file mode 100644
index 0000000..defc69b
--- /dev/null
+++ b/Test/baseResults/spv.register.subpass.frag.out
@@ -0,0 +1,76 @@
+spv.register.subpass.frag
+// Module Version 10000
+// Generated by (magic number): 80001
+// Id's are bound by 40
+
+                              Capability Shader
+                              Capability StorageImageMultisample
+                              Capability InputAttachment
+               1:             ExtInstImport  "GLSL.std.450"
+                              MemoryModel Logical GLSL450
+                              EntryPoint Fragment 4  "main" 38
+                              ExecutionMode 4 OriginUpperLeft
+                              Source HLSL 500
+                              Name 4  "main"
+                              Name 9  "@main("
+                              Name 12  "result00"
+                              Name 15  "subpass_f4"
+                              Name 22  "result10"
+                              Name 25  "subpass_ms_f4"
+                              Name 29  "result73"
+                              Name 30  "subpass_2"
+                              Name 38  "@entryPointOutput"
+                              Decorate 15(subpass_f4) DescriptorSet 0
+                              Decorate 15(subpass_f4) Binding 21
+                              Decorate 15(subpass_f4) InputAttachmentIndex 1
+                              Decorate 25(subpass_ms_f4) DescriptorSet 0
+                              Decorate 25(subpass_ms_f4) Binding 20
+                              Decorate 25(subpass_ms_f4) InputAttachmentIndex 4
+                              Decorate 30(subpass_2) DescriptorSet 0
+                              Decorate 30(subpass_2) Binding 22
+                              Decorate 30(subpass_2) InputAttachmentIndex 7
+                              Decorate 38(@entryPointOutput) Location 0
+               2:             TypeVoid
+               3:             TypeFunction 2
+               6:             TypeFloat 32
+               7:             TypeVector 6(float) 4
+               8:             TypeFunction 7(fvec4)
+              11:             TypePointer Function 7(fvec4)
+              13:             TypeImage 6(float) SubpassData nonsampled format:Unknown
+              14:             TypePointer UniformConstant 13
+  15(subpass_f4):     14(ptr) Variable UniformConstant
+              17:             TypeInt 32 1
+              18:     17(int) Constant 0
+              19:             TypeVector 17(int) 2
+              20:   19(ivec2) ConstantComposite 18 18
+              23:             TypeImage 6(float) SubpassData multi-sampled nonsampled format:Unknown
+              24:             TypePointer UniformConstant 23
+25(subpass_ms_f4):     24(ptr) Variable UniformConstant
+              27:     17(int) Constant 3
+   30(subpass_2):     14(ptr) Variable UniformConstant
+              33:    6(float) Constant 0
+              34:    7(fvec4) ConstantComposite 33 33 33 33
+              37:             TypePointer Output 7(fvec4)
+38(@entryPointOutput):     37(ptr) Variable Output
+         4(main):           2 Function None 3
+               5:             Label
+              39:    7(fvec4) FunctionCall 9(@main()
+                              Store 38(@entryPointOutput) 39
+                              Return
+                              FunctionEnd
+       9(@main():    7(fvec4) Function None 8
+              10:             Label
+    12(result00):     11(ptr) Variable Function
+    22(result10):     11(ptr) Variable Function
+    29(result73):     11(ptr) Variable Function
+              16:          13 Load 15(subpass_f4)
+              21:    7(fvec4) ImageRead 16 20
+                              Store 12(result00) 21
+              26:          23 Load 25(subpass_ms_f4)
+              28:    7(fvec4) ImageRead 26 20 Sample 27
+                              Store 22(result10) 28
+              31:          13 Load 30(subpass_2)
+              32:    7(fvec4) ImageRead 31 20
+                              Store 29(result73) 32
+                              ReturnValue 34
+                              FunctionEnd
diff --git a/Test/hlsl.subpass.frag b/Test/hlsl.subpass.frag
new file mode 100644
index 0000000..20a717f
--- /dev/null
+++ b/Test/hlsl.subpass.frag
@@ -0,0 +1,113 @@
+
+layout(input_attachment_index = 1) SubpassInput<float4> subpass_f4 : register(t1);
+layout(input_attachment_index = 2) SubpassInput<int4>   subpass_i4;
+layout(input_attachment_index = 3) SubpassInput<uint4>  subpass_u4;
+
+layout(input_attachment_index = 4) SubpassInputMS<float4> subpass_ms_f4;
+layout(input_attachment_index = 5) SubpassInputMS<int4>   subpass_ms_i4;
+layout(input_attachment_index = 6) SubpassInputMS<uint4>  subpass_ms_u4;
+
+layout(input_attachment_index = 1) SubpassInput<float3> subpass_f3;
+layout(input_attachment_index = 2) SubpassInput<int3>   subpass_i3;
+layout(input_attachment_index = 3) SubpassInput<uint3>  subpass_u3;
+
+layout(input_attachment_index = 4) SubpassInputMS<float3> subpass_ms_f3;
+layout(input_attachment_index = 5) SubpassInputMS<int3>   subpass_ms_i3;
+layout(input_attachment_index = 6) SubpassInputMS<uint3>  subpass_ms_u3;
+
+layout(input_attachment_index = 1) SubpassInput<float2> subpass_f2;
+layout(input_attachment_index = 2) SubpassInput<int2>   subpass_i2;
+layout(input_attachment_index = 3) SubpassInput<uint2>  subpass_u2;
+
+layout(input_attachment_index = 4) SubpassInputMS<float2> subpass_ms_f2;
+layout(input_attachment_index = 5) SubpassInputMS<int2>   subpass_ms_i2;
+layout(input_attachment_index = 6) SubpassInputMS<uint2>  subpass_ms_u2;
+
+layout(input_attachment_index = 1) SubpassInput<float> subpass_f;
+layout(input_attachment_index = 2) SubpassInput<int>   subpass_i;
+layout(input_attachment_index = 3) SubpassInput<uint>  subpass_u;
+
+layout(input_attachment_index = 4) SubpassInputMS<float> subpass_ms_f;
+layout(input_attachment_index = 5) SubpassInputMS<int>   subpass_ms_i;
+layout(input_attachment_index = 6) SubpassInputMS<uint>  subpass_ms_u;
+
+[[vk::input_attachment_index(7)]] SubpassInput subpass_2;
+
+struct mystruct_f_t
+{
+    float  c0;
+    float2 c1;
+    float  c2;
+};
+
+struct mystruct_i_t
+{
+    int  c0;
+    int2 c1;
+    int  c2;
+};
+
+struct mystruct_u_t
+{
+    uint  c0;
+    uint2 c1;
+    uint  c2;
+};
+
+// TODO: ...
+// layout(input_attachment_index = 7) SubpassInput<mystruct_f_t>    subpass_fs;
+// layout(input_attachment_index = 8) SubpassInputMS<mystruct_f_t>  subpass_ms_fs;
+
+// layout(input_attachment_index = 7) SubpassInput<mystruct_i_t>    subpass_is;
+// layout(input_attachment_index = 8) SubpassInputMS<mystruct_i_t>  subpass_ms_is;
+
+// layout(input_attachment_index = 7) SubpassInput<mystruct_u_t>    subpass_us;
+// layout(input_attachment_index = 8) SubpassInputMS<mystruct_u_t>  subpass_ms_us;
+
+float4 main() : SV_Target0
+{
+    float4 result00 = subpass_f4.SubpassLoad();
+    int4   result01 = subpass_i4.SubpassLoad();
+    uint4  result02 = subpass_u4.SubpassLoad();
+
+    float4 result10 = subpass_ms_f4.SubpassLoad(3);
+    int4   result11 = subpass_ms_i4.SubpassLoad(3);
+    uint4  result12 = subpass_ms_u4.SubpassLoad(3);
+
+    float3 result20 = subpass_f3.SubpassLoad();
+    int3   result21 = subpass_i3.SubpassLoad();
+    uint3  result22 = subpass_u3.SubpassLoad();
+
+    float3 result30 = subpass_ms_f3.SubpassLoad(3);
+    int3   result31 = subpass_ms_i3.SubpassLoad(3);
+    uint3  result32 = subpass_ms_u3.SubpassLoad(3);
+
+    float2 result40 = subpass_f2.SubpassLoad();
+    int2   result41 = subpass_i2.SubpassLoad();
+    uint2  result42 = subpass_u2.SubpassLoad();
+
+    float2 result50 = subpass_ms_f2.SubpassLoad(2);
+    int2   result51 = subpass_ms_i2.SubpassLoad(2);
+    uint2  result52 = subpass_ms_u2.SubpassLoad(2);
+
+    float  result60 = subpass_f.SubpassLoad();
+    int    result61 = subpass_i.SubpassLoad();
+    uint   result62 = subpass_u.SubpassLoad();
+
+    float  result70 = subpass_ms_f.SubpassLoad(2);
+    int    result71 = subpass_ms_i.SubpassLoad(2);
+    uint   result72 = subpass_ms_u.SubpassLoad(2);
+
+    float4 result73 = subpass_2.SubpassLoad();
+
+    // TODO: 
+    // mystruct_f_t result80 = subpass_fs.SubpassLoad();
+    // mystruct_i_t result81 = subpass_is.SubpassLoad();
+    // mystruct_u_t result82 = subpass_us.SubpassLoad();
+
+    // mystruct_f_t result90 = subpass_ms_sf.SubpassLoad(2);
+    // mystruct_i_t result91 = subpass_ms_if.SubpassLoad(2);
+    // mystruct_u_t result92 = subpass_ms_uf.SubpassLoad(2);
+
+    return 0;
+}
diff --git a/Test/spv.register.subpass.frag b/Test/spv.register.subpass.frag
new file mode 100644
index 0000000..281c2f7
--- /dev/null
+++ b/Test/spv.register.subpass.frag
@@ -0,0 +1,15 @@
+
+// Test binding autoassignment and offset for SubpassInput objects
+
+layout(input_attachment_index = 1) SubpassInput<float4> subpass_f4 : register(t1);
+layout(input_attachment_index = 4) SubpassInputMS<float4> subpass_ms_f4;
+[[vk::input_attachment_index(7)]] SubpassInput subpass_2;
+
+float4 main() : SV_Target0
+{
+    float4 result00 = subpass_f4.SubpassLoad();
+    float4 result10 = subpass_ms_f4.SubpassLoad(3);
+    float4 result73 = subpass_2.SubpassLoad();
+
+    return 0;
+}
diff --git a/glslang/MachineIndependent/intermOut.cpp b/glslang/MachineIndependent/intermOut.cpp
index ae68216..7e15392 100644
--- a/glslang/MachineIndependent/intermOut.cpp
+++ b/glslang/MachineIndependent/intermOut.cpp
@@ -196,6 +196,7 @@
     case EOpLogicalOr:  out.debug << "logical-or";   break;
     case EOpLogicalXor: out.debug << "logical-xor"; break;
     case EOpLogicalAnd: out.debug << "logical-and"; break;
+
     default: out.debug << "<unknown op>";
     }
 
@@ -491,6 +492,9 @@
     case EOpConvUint16ToUint64:     out.debug << "Convert uint16 to uint64";    break;
 #endif
 
+    case EOpSubpassLoad:   out.debug << "subpassLoad";   break;
+    case EOpSubpassLoadMS: out.debug << "subpassLoadMS"; break;
+
     default: out.debug.message(EPrefixError, "Bad unary op");
     }
 
@@ -791,6 +795,9 @@
     case EOpWorkgroupMemoryBarrier:           out.debug << "WorkgroupMemoryBarrier";           break;
     case EOpWorkgroupMemoryBarrierWithGroupSync: out.debug << "WorkgroupMemoryBarrierWithGroupSync"; break;
 
+    case EOpSubpassLoad:   out.debug << "subpassLoad";   break;
+    case EOpSubpassLoadMS: out.debug << "subpassLoadMS"; break;
+
     default: out.debug.message(EPrefixError, "Bad aggregation op");
     }
 
diff --git a/glslang/MachineIndependent/iomapper.cpp b/glslang/MachineIndependent/iomapper.cpp
index 1758d00..4926cf8 100644
--- a/glslang/MachineIndependent/iomapper.cpp
+++ b/glslang/MachineIndependent/iomapper.cpp
@@ -497,7 +497,8 @@
     }
 
     static bool isTextureType(const glslang::TType& type) {
-        return type.getBasicType() == glslang::EbtSampler && type.getSampler().isTexture();
+        return (type.getBasicType() == glslang::EbtSampler && 
+                (type.getSampler().isTexture() || type.getSampler().isSubpass()));
     }
 
     static bool isUboType(const glslang::TType& type) {
diff --git a/gtests/Hlsl.FromFile.cpp b/gtests/Hlsl.FromFile.cpp
index dfdadf5..0ba399f 100644
--- a/gtests/Hlsl.FromFile.cpp
+++ b/gtests/Hlsl.FromFile.cpp
@@ -318,6 +318,7 @@
         {"hlsl.structin.vert", "main"},
         {"hlsl.structIoFourWay.frag", "main"},
         {"hlsl.structStructName.frag", "main"},
+        {"hlsl.subpass.frag", "main"},
         {"hlsl.synthesizeInput.frag", "main"},
         {"hlsl.texture.struct.frag", "main"},
         {"hlsl.texture.subvec4.frag", "main"},
diff --git a/gtests/Spv.FromFile.cpp b/gtests/Spv.FromFile.cpp
index c37e460..63992f1 100644
--- a/gtests/Spv.FromFile.cpp
+++ b/gtests/Spv.FromFile.cpp
@@ -334,6 +334,7 @@
         { "spv.register.autoassign.frag", "main_ep", 5, 10, 0, 20, 30, true, false },
         { "spv.register.noautoassign.frag", "main_ep", 5, 10, 0, 15, 30, false, false },
         { "spv.register.autoassign-2.frag", "main", 5, 10, 0, 15, 30, true, true },
+        { "spv.register.subpass.frag", "main", 0, 20, 0, 0, 0, true, true },
         { "spv.buffer.autoassign.frag", "main", 5, 10, 0, 15, 30, true, true },
         { "spv.ssbo.autoassign.frag", "main", 5, 10, 0, 15, 30, true, true },
         { "spv.ssboAlias.frag", "main", 0, 0, 0, 0, 83, true, false },
diff --git a/hlsl/hlslGrammar.cpp b/hlsl/hlslGrammar.cpp
index 4914f20..88eacd9 100755
--- a/hlsl/hlslGrammar.cpp
+++ b/hlsl/hlslGrammar.cpp
@@ -1088,6 +1088,69 @@
     return true;
 }
 
+// subpass input type
+//      : SUBPASSINPUT
+//      | SUBPASSINPUT VECTOR LEFT_ANGLE template_type RIGHT_ANGLE
+//      | SUBPASSINPUTMS
+//      | SUBPASSINPUTMS VECTOR LEFT_ANGLE template_type RIGHT_ANGLE
+bool HlslGrammar::acceptSubpassInputType(TType& type)
+{
+    // read subpass type
+    const EHlslTokenClass subpassInputType = peek();
+
+    bool multisample;
+
+    switch (subpassInputType) {
+    case EHTokSubpassInput:   multisample = false; break;
+    case EHTokSubpassInputMS: multisample = true;  break;
+    default:
+        return false;  // not a subpass input declaration
+    }
+
+    advanceToken();  // consume the sampler type keyword
+
+    TType subpassType(EbtFloat, EvqUniform, 4); // default type is float4
+
+    if (acceptTokenClass(EHTokLeftAngle)) {
+        if (! acceptType(subpassType)) {
+            expected("scalar or vector type");
+            return false;
+        }
+
+        const TBasicType basicRetType = subpassType.getBasicType() ;
+
+        switch (basicRetType) {
+        case EbtFloat:
+        case EbtUint:
+        case EbtInt:
+        case EbtStruct:
+            break;
+        default:
+            unimplemented("basic type in subpass input");
+            return false;
+        }
+
+        if (! acceptTokenClass(EHTokRightAngle)) {
+            expected("right angle bracket");
+            return false;
+        }
+    }
+
+    const TBasicType subpassBasicType = subpassType.isStruct() ? (*subpassType.getStruct())[0].type->getBasicType()
+        : subpassType.getBasicType();
+
+    TSampler sampler;
+    sampler.setSubpass(subpassBasicType, multisample);
+
+    // Remember the declared return type.  Function returns false on error.
+    if (!parseContext.setTextureReturnType(sampler, subpassType, token.loc))
+        return false;
+
+    type.shallowCopy(TType(sampler, EvqUniform));
+
+    return true;
+}
+
 // sampler_type
 //      : SAMPLER
 //      | SAMPLER1D
@@ -1357,6 +1420,11 @@
         return acceptSamplerType(type);
         break;
 
+    case EHTokSubpassInput:           // fall through
+    case EHTokSubpassInputMS:         // ...
+        return acceptSubpassInputType(type);
+        break;
+
     case EHTokBuffer:                 // fall through
     case EHTokTexture1d:              // ...
     case EHTokTexture1darray:         // ...
diff --git a/hlsl/hlslGrammar.h b/hlsl/hlslGrammar.h
index 2db0754..f0adfa0 100755
--- a/hlsl/hlslGrammar.h
+++ b/hlsl/hlslGrammar.h
@@ -87,6 +87,7 @@
         bool acceptAnnotations(TQualifier&);
         bool acceptSamplerType(TType&);
         bool acceptTextureType(TType&);
+        bool acceptSubpassInputType(TType&);
         bool acceptStructBufferType(TType&);
         bool acceptConstantBufferType(TType&);
         bool acceptStruct(TType&, TIntermNode*& nodeList);
diff --git a/hlsl/hlslParseHelper.cpp b/hlsl/hlslParseHelper.cpp
index f414085..91deb4f 100755
--- a/hlsl/hlslParseHelper.cpp
+++ b/hlsl/hlslParseHelper.cpp
@@ -4215,6 +4215,25 @@
             break;
         }
 
+    case EOpSubpassLoad:
+        {
+            const TIntermTyped* argSubpass = 
+                argAggregate ? argAggregate->getSequence()[0]->getAsTyped() :
+                arguments->getAsTyped();
+
+            const TSampler& sampler = argSubpass->getType().getSampler();
+
+            // subpass load: the multisample form is overloaded.  Here, we convert that to
+            // the EOpSubpassLoadMS opcode.
+            if (argAggregate != nullptr && argAggregate->getSequence().size() > 1)
+                node->getAsOperator()->setOp(EOpSubpassLoadMS);
+
+            node = convertReturn(node, sampler);
+
+            break;
+        }
+        
+
     default:
         break; // most pass through unchanged
     }
@@ -8952,6 +8971,12 @@
         return false;
     }
 
+    // TODO: Subpass doesn't handle struct returns, due to some oddities with fn overloading.
+    if (sampler.isSubpass()) {
+        error(loc, "Unimplemented: structure template type in subpass input", "", "");
+        return false;
+    }
+
     TTypeList* members = retType.getWritableStruct();
 
     // Check for too many or not enough structure members.
diff --git a/hlsl/hlslParseables.cpp b/hlsl/hlslParseables.cpp
index db67c39..31f6801 100755
--- a/hlsl/hlslParseables.cpp
+++ b/hlsl/hlslParseables.cpp
@@ -68,14 +68,21 @@
     }
 }
 
-bool IsSamplerType(const char argType) { return argType == 'S' || argType == 's'; }
-bool IsArrayed(const char argOrder)    { return argOrder == '@' || argOrder == '&' || argOrder == '#'; }
-bool IsTextureMS(const char argOrder)  { return argOrder == '$' || argOrder == '&'; }
-bool IsBuffer(const char argOrder)     { return argOrder == '*' || argOrder == '~'; }
-bool IsImage(const char argOrder)      { return argOrder == '!' || argOrder == '#' || argOrder == '~'; }
+// arg order queries
+bool IsSamplerType(const char argType)     { return argType == 'S' || argType == 's'; }
+bool IsArrayed(const char argOrder)        { return argOrder == '@' || argOrder == '&' || argOrder == '#'; }
+bool IsTextureNonMS(const char argOrder)   { return argOrder == '%'; }
+bool IsSubpassInput(const char argOrder)   { return argOrder == '[' || argOrder == ']'; }
+bool IsArrayedTexture(const char argOrder) { return argOrder == '@'; }
+bool IsTextureMS(const char argOrder)      { return argOrder == '$' || argOrder == '&'; }
+bool IsMS(const char argOrder)             { return IsTextureMS(argOrder) || argOrder == ']'; }
+bool IsBuffer(const char argOrder)         { return argOrder == '*' || argOrder == '~'; }
+bool IsImage(const char argOrder)          { return argOrder == '!' || argOrder == '#' || argOrder == '~'; }
+
 bool IsTextureType(const char argOrder)
 {
-    return argOrder == '%' || argOrder == '@' || IsTextureMS(argOrder) || IsBuffer(argOrder) | IsImage(argOrder);
+    return IsTextureNonMS(argOrder) || IsArrayedTexture(argOrder) ||
+           IsTextureMS(argOrder) || IsBuffer(argOrder) || IsImage(argOrder);
 }
 
 // Reject certain combinations that are illegal sample methods.  For example,
@@ -222,15 +229,16 @@
     const bool isTexture   = IsTextureType(argOrder[0]);
     const bool isArrayed   = IsArrayed(argOrder[0]);
     const bool isSampler   = IsSamplerType(argType[0]);
-    const bool isMS        = IsTextureMS(argOrder[0]);
+    const bool isMS        = IsMS(argOrder[0]);
     const bool isBuffer    = IsBuffer(argOrder[0]);
     const bool isImage     = IsImage(argOrder[0]);
+    const bool isSubpass   = IsSubpassInput(argOrder[0]);
 
     char type  = *argType;
 
     if (isTranspose) {  // Take transpose of matrix dimensions
         std::swap(dim0, dim1);
-    } else if (isTexture) {
+    } else if (isTexture || isSubpass) {
         if (type == 'F')       // map base type to texture of that type.
             type = 'T';        // e.g, int -> itexture, uint -> utexture, etc.
         else if (type == 'I')
@@ -255,16 +263,23 @@
         case 'S': s += "sampler";                             break;
         case 's': s += "SamplerComparisonState";              break;
         case 'T': s += ((isBuffer && isImage) ? "RWBuffer" :
+                        isSubpass ? "SubpassInput" :
                         isBuffer ? "Buffer" :
                         isImage  ? "RWTexture" : "Texture");  break;
         case 'i': s += ((isBuffer && isImage) ? "RWBuffer" :
+                        isSubpass ? "SubpassInput" :
                         isBuffer ? "Buffer" :
                         isImage ? "RWTexture" : "Texture");   break;
         case 'u': s += ((isBuffer && isImage) ? "RWBuffer" :
+                        isSubpass ? "SubpassInput" :
                         isBuffer ? "Buffer" :
                         isImage ? "RWTexture" : "Texture");   break;
         default:  s += "UNKNOWN_TYPE";                        break;
         }
+
+        if (isSubpass && isMS)
+            s += "MS";
+
     } else {
         switch (type) {
         case '-': s += "void"; break;
@@ -282,6 +297,7 @@
                 s += type;
 
             s += ((isImage && isBuffer) ? "imageBuffer"   :
+                  isSubpass             ? "subpassInput" :
                   isImage               ? "image"         :
                   isBuffer              ? "samplerBuffer" :
                   "texture");
@@ -296,6 +312,9 @@
     if (fixedVecSize != 0)
         dim0 = dim1 = fixedVecSize;
 
+    const char dim0Char = ('0' + char(dim0));
+    const char dim1Char = ('0' + char(dim1));
+
     // Add sampler dimensions
     if (isSampler || isTexture) {
         if ((order == 'V' || isTexture) && !isBuffer) {
@@ -320,12 +339,12 @@
         case '-': break;  // no dimensions for voids
         case 'S': break;  // no dimensions on scalars
         case 'V':
-            s += ('0' + char(dim0));
+            s += dim0Char;
             break;
         case 'M':
-            s += ('0' + char(dim0));
+            s += dim0Char;
             s += 'x';
-            s += ('0' + char(dim1));
+            s += dim1Char;
             break;
         default:
             break;
@@ -339,9 +358,9 @@
     // For HLSL, append return type for texture types
     if (UseHlslTypes) {
         switch (type) {
-        case 'i': s += "<int4>";   break;
-        case 'u': s += "<uint4>";  break;
-        case 'T': s += "<float4>"; break;
+        case 'i': s += "<int";   s += dim0Char; s += ">"; break;
+        case 'u': s += "<uint";  s += dim0Char; s += ">"; break;
+        case 'T': s += "<float"; s += dim0Char; s += ">"; break;
         default: break;
         }
     }
@@ -414,7 +433,7 @@
         const char* nthArgOrder(NthArg(argOrder, arg));
         if (nthArgOrder == nullptr)
             break;
-        else if (*nthArgOrder == 'V')
+        else if (*nthArgOrder == 'V' || IsSubpassInput(*nthArgOrder))
             dim0Max = 4;
         else if (*nthArgOrder == 'M')
             dim0Max = dim1Max = 4;
@@ -537,6 +556,7 @@
     // '!' as first letter of order creates image object
     // '#' as first letter of order creates arrayed image object
     // '~' as first letter of order creates an image buffer object
+    // '[' / ']' as first letter of order creates a SubpassInput/SubpassInputMS object
 
     static const struct {
         const char*   name;      // intrinsic name
@@ -882,6 +902,10 @@
         { "DecrementCounter",                 nullptr, nullptr,   "-",              "-",              EShLangAll,   true },
         { "Consume",                          nullptr, nullptr,   "-",              "-",              EShLangAll,   true },
 
+        // Methods for subpass input objects
+        { "SubpassLoad",                      "V4",    nullptr,   "[",              "FIU",            EShLangPS,    true },
+        { "SubpassLoad",                      "V4",    nullptr,   "],S",            "FIU,I",          EShLangPS,    true },
+
         // Mark end of list, since we want to avoid a range-based for, as some compilers don't handle it yet.
         { nullptr,                            nullptr, nullptr,   nullptr,      nullptr,  0, false },
     };
@@ -1219,6 +1243,10 @@
     // GS methods
     symbolTable.relateToOperator(BUILTIN_PREFIX "Append",                      EOpMethodAppend);
     symbolTable.relateToOperator(BUILTIN_PREFIX "RestartStrip",                EOpMethodRestartStrip);
+
+    // Subpass input methods
+    symbolTable.relateToOperator(BUILTIN_PREFIX "SubpassLoad",                 EOpSubpassLoad);
+    symbolTable.relateToOperator(BUILTIN_PREFIX "SubpassLoadMS",               EOpSubpassLoadMS);
 }
 
 //
diff --git a/hlsl/hlslScanContext.cpp b/hlsl/hlslScanContext.cpp
index 392efeb..c16fdfa 100755
--- a/hlsl/hlslScanContext.cpp
+++ b/hlsl/hlslScanContext.cpp
@@ -336,6 +336,8 @@
     (*KeywordMap)["RWTexture2DArray"] =        EHTokRWTexture2darray;
     (*KeywordMap)["RWTexture3D"] =             EHTokRWTexture3d;
     (*KeywordMap)["RWBuffer"] =                EHTokRWBuffer;
+    (*KeywordMap)["SubpassInput"] =            EHTokSubpassInput;
+    (*KeywordMap)["SubpassInputMS"] =          EHTokSubpassInputMS;
 
     (*KeywordMap)["AppendStructuredBuffer"] =  EHTokAppendStructuredBuffer;
     (*KeywordMap)["ByteAddressBuffer"] =       EHTokByteAddressBuffer;
@@ -827,6 +829,8 @@
     case EHTokRWByteAddressBuffer:
     case EHTokRWStructuredBuffer:
     case EHTokStructuredBuffer:
+    case EHTokSubpassInput:
+    case EHTokSubpassInputMS:
         return keyword;
 
     // variable, user type, ...
diff --git a/hlsl/hlslTokens.h b/hlsl/hlslTokens.h
index 15de63a..1c827bf 100755
--- a/hlsl/hlslTokens.h
+++ b/hlsl/hlslTokens.h
@@ -273,6 +273,8 @@
     EHTokRWTexture2darray,
     EHTokRWTexture3d,
     EHTokRWBuffer,
+    EHTokSubpassInput,
+    EHTokSubpassInputMS,
 
     // Structure buffer variants
     EHTokAppendStructuredBuffer,