Add a -disable-16bit flag and associated support for experimenting with
disabling the use of 16-bit operations on x86. This doesn't yet work for
inline asms with 16-bit constraints, vectors with 16-bit elements,
trampoline code, and perhaps other obscurities, but it's enough to try
some experiments.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80930 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index c8815c0..55c2eb4 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -565,7 +565,7 @@
                     [(X86retflag 0)]>;
   def RETI   : Ii16<0xC2, RawFrm, (outs), (ins i16imm:$amt, variable_ops),
                     "ret\t$amt",
-                    [(X86retflag imm:$amt)]>;
+                    [(X86retflag timm:$amt)]>;
 }
 
 // All branches are RawFrm, Void, Branch, and Terminators
@@ -4168,6 +4168,18 @@
                     (implicit EFLAGS)),
           (DEC32m addr:$dst)>, Requires<[In32BitMode]>;
 
+// -disable-16bit support.
+def : Pat<(truncstorei16 (i32 imm:$src), addr:$dst),
+          (MOV16mi addr:$dst, imm:$src)>;
+def : Pat<(truncstorei16 GR32:$src, addr:$dst),
+          (MOV16mr addr:$dst, (EXTRACT_SUBREG GR32:$src, x86_subreg_16bit))>;
+def : Pat<(i32 (sextloadi16 addr:$dst)),
+          (MOVSX32rm16 addr:$dst)>;
+def : Pat<(i32 (zextloadi16 addr:$dst)),
+          (MOVZX32rm16 addr:$dst)>;
+def : Pat<(i32 (extloadi16 addr:$dst)),
+          (MOVZX32rm16 addr:$dst)>;
+
 //===----------------------------------------------------------------------===//
 // Floating Point Stack Support
 //===----------------------------------------------------------------------===//