[MC][AMDGPU] Consume EndOfStatement in asm parser

[scott.linder]

Summary

Avoids spurious newlines showing up in the output when emitting assembly
via MC.

[MaskRay]

LGTM.

[scott.linder]

Rebase over https://reviews.llvm.org/D92084

I think I need some input on how best to handle this. I'm not particularly
happy with what I have right now, but after spending some time trying to do
better and not making much progress I thought I would ask if anyone else has a
better idea.

[dp]

I'd have reverted to using IDLoc because the error message is clear enough.
I'm sorry that my change caused such trouble.
The better is the enemy of the good :-)

[scott.linder]

In D92690#2442357, @dp wrote:

I'd have reverted to using IDLoc because the error message is clear enough.
I'm sorry that my change caused such trouble.
The better is the enemy of the good :-)

That makes sense to me, I probably should have asked first :^)

I also realized after having slept on it that my current patch doesn't work for any non-ascii input anyway.

I will just revert that part of your earlier change and put up a review for it separately, then this patch should rebase cleanly.

[scott.linder]

Rebase the original version of the patch again; this is the same diff that was
approved already, so I am going to just go ahead and commit it. If anyone has
any objections I can open another review to address them.

llvm/lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp

if (Res != MatchOperand_Success) {
         StringRef Msg =
           (Res == MatchOperand_ParseFail) ? "failed parsing operand." :
                                             "not a valid operand.";
         Error(getLexer().getLoc(), Msg);
       }
       while (!getLexer().is(AsmToken::EndOfStatement)) {
         Parser.Lex();
       }
+      Parser.Lex();
       return true;
     }
   }
+  Parser.Lex();
 
   return false;
 }
 
 //===----------------------------------------------------------------------===//
 // Utility functions
 //===----------------------------------------------------------------------===//
 

llvm/test/MC/AMDGPU/round-trip.s

+# RUN: llvm-mc -preserve-comments -triple amdgcn-amd-amdhsa %s >%t-1.s
+# RUN: llvm-mc -preserve-comments -triple amdgcn-amd-amdhsa %t-1.s >%t-2.s
+# RUN: diff %t-1.s %t-2.s
+
+# Test that AMDGPU assembly round-trips when run through MC; the first
+# transition from hand-written to "canonical" output may introduce some small
+# differences, so we don't include the initial input in the comparison.
+
+.text
+
+# The AMDGPU asm parser didn't consume the end of statement
+# consistently, which led to extra empty lines in the output.
+s_nop 0