DI: Remove DW_TAG_arg_variable and DW_TAG_auto_variable

Remove the fake `DW_TAG_auto_variable` and `DW_TAG_arg_variable` tags,
using `DW_TAG_variable` in their place Stop exposing the `tag:` field at
all in the assembly format for `DILocalVariable`.

Most of the testcase updates were generated by the following sed script:

    find test/ -name "*.ll" -o -name "*.mir" |
    xargs grep -l 'DILocalVariable' |
    xargs sed -i '' \
      -e 's/tag: DW_TAG_arg_variable, //' \
      -e 's/tag: DW_TAG_auto_variable, //'

There were only a handful of tests in `test/Assembly` that I needed to
update by hand.

(Note: a follow-up could change `DILocalVariable::DILocalVariable()` to
set the tag to `DW_TAG_formal_parameter` instead of `DW_TAG_variable`
(as appropriate), instead of having that logic magically in the backend
in `DbgVariable`.  I've added a FIXME to that effect.)

llvm-svn: 243774
diff --git a/llvm/test/Transforms/Inline/ignore-debug-info.ll b/llvm/test/Transforms/Inline/ignore-debug-info.ll
index eb92bc5..4cc4bde 100644
--- a/llvm/test/Transforms/Inline/ignore-debug-info.ll
+++ b/llvm/test/Transforms/Inline/ignore-debug-info.ll
@@ -12,11 +12,11 @@
 
 define <4 x float> @inner_vectors(<4 x float> %a, <4 x float> %b) {
 entry:
-  call void @llvm.dbg.value(metadata i32 undef, i64 0, metadata !DILocalVariable(tag: DW_TAG_auto_variable, scope: !6), metadata !DIExpression()), !dbg !DILocation(scope: !6)
+  call void @llvm.dbg.value(metadata i32 undef, i64 0, metadata !DILocalVariable(scope: !6), metadata !DIExpression()), !dbg !DILocation(scope: !6)
   %mul = fmul <4 x float> %a, <float 3.000000e+00, float 3.000000e+00, float 3.000000e+00, float 3.000000e+00>
-  call void @llvm.dbg.value(metadata i32 undef, i64 0, metadata !DILocalVariable(tag: DW_TAG_auto_variable, scope: !6), metadata !DIExpression()), !dbg !DILocation(scope: !6)
+  call void @llvm.dbg.value(metadata i32 undef, i64 0, metadata !DILocalVariable(scope: !6), metadata !DIExpression()), !dbg !DILocation(scope: !6)
   %mul1 = fmul <4 x float> %b, <float 5.000000e+00, float 5.000000e+00, float 5.000000e+00, float 5.000000e+00>
-  call void @llvm.dbg.value(metadata i32 undef, i64 0, metadata !DILocalVariable(tag: DW_TAG_auto_variable, scope: !6), metadata !DIExpression()), !dbg !DILocation(scope: !6)
+  call void @llvm.dbg.value(metadata i32 undef, i64 0, metadata !DILocalVariable(scope: !6), metadata !DIExpression()), !dbg !DILocation(scope: !6)
   %add = fadd <4 x float> %mul, %mul1
   ret <4 x float> %add
 }
@@ -27,10 +27,10 @@
 ; CHECK: ret float
 
 entry:
-  call void @llvm.dbg.value(metadata i32 undef, i64 0, metadata !DILocalVariable(tag: DW_TAG_auto_variable, scope: !6), metadata !DIExpression()), !dbg !DILocation(scope: !6)
-  call void @llvm.dbg.value(metadata i32 undef, i64 0, metadata !DILocalVariable(tag: DW_TAG_auto_variable, scope: !6), metadata !DIExpression()), !dbg !DILocation(scope: !6)
+  call void @llvm.dbg.value(metadata i32 undef, i64 0, metadata !DILocalVariable(scope: !6), metadata !DIExpression()), !dbg !DILocation(scope: !6)
+  call void @llvm.dbg.value(metadata i32 undef, i64 0, metadata !DILocalVariable(scope: !6), metadata !DIExpression()), !dbg !DILocation(scope: !6)
   %call = call <4 x float> @inner_vectors(<4 x float> %a, <4 x float> %b)
-  call void @llvm.dbg.value(metadata i32 undef, i64 0, metadata !DILocalVariable(tag: DW_TAG_auto_variable, scope: !6), metadata !DIExpression()), !dbg !DILocation(scope: !6)
+  call void @llvm.dbg.value(metadata i32 undef, i64 0, metadata !DILocalVariable(scope: !6), metadata !DIExpression()), !dbg !DILocation(scope: !6)
   %vecext = extractelement <4 x float> %call, i32 0
   %vecext1 = extractelement <4 x float> %call, i32 1
   %add = fadd float %vecext, %vecext1