I have manually decoded the imm field of an insertps one too many

times.  This patch causes llc and llvm-mc (which both default to
verbose-asm) to print out comments after a few common shuffle 
instructions which indicates the shuffle mask, e.g.:

	insertps	$113, %xmm3, %xmm0     ## xmm0 = zero,xmm0[1,2],xmm3[1]
	unpcklps	%xmm1, %xmm0    ## xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1]
	pshufd	$1, %xmm1, %xmm1        ## xmm1 = xmm1[1,0,0,0]

This is carefully factored to keep the information extraction (of the
shuffle mask) separate from the printing logic.  I plan to move the
extraction part out somewhere else at some point for other parts of
the x86 backend that want to introspect on the behavior of shuffles.

llvm-svn: 112387

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/AsmPrinter/X86ATTInstPrinter.cpp b/llvm/lib/Target/X86/AsmPrinter/X86ATTInstPrinter.cpp
index f2cdb5ba55e..554b96c96e0 100644
--- a/llvm/lib/Target/X86/AsmPrinter/X86ATTInstPrinter.cpp
+++ b/llvm/lib/Target/X86/AsmPrinter/X86ATTInstPrinter.cpp
@@ -14,6 +14,7 @@
 
 #define DEBUG_TYPE "asm-printer"
 #include "X86ATTInstPrinter.h"
+#include "X86InstComments.h"
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCExpr.h"
@@ -31,6 +32,10 @@ using namespace llvm;
 
 void X86ATTInstPrinter::printInst(const MCInst *MI, raw_ostream &OS) {
   printInstruction(MI, OS);
+  
+  // If verbose assembly is enabled, we can print some informative comments.
+  if (CommentStream)
+    EmitAnyX86InstComments(MI, *CommentStream, getRegisterName);
 }
 StringRef X86ATTInstPrinter::getOpcodeName(unsigned Opcode) const {
   return getInstructionName(Opcode);