Lower FrameIndex operand of DEBUG_VALUE (specially) and

print it as a comment on X86.

llvm-svn: 93499

1 files changed, 9 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/X86RegisterInfo.cpp b/llvm/lib/Target/X86/X86RegisterInfo.cpp
index d96aafda603..9bd96af6c75 100644
--- a/llvm/lib/Target/X86/X86RegisterInfo.cpp
+++ b/llvm/lib/Target/X86/X86RegisterInfo.cpp
@@ -591,6 +591,15 @@ X86RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
   int FrameIndex = MI.getOperand(i).getIndex();
   unsigned BasePtr;
 
+  // DEBUG_VALUE has a special representation, and is only robust enough to
+  // represent SP(or BP) +- offset addressing modes.  We rewrite the
+  // FrameIndex to be a constant; implicitly positive constants are relative
+  // to ESP and negative ones to EBP.
+  if (MI.getOpcode()==TargetInstrInfo::DEBUG_VALUE) {
+    MI.getOperand(i).ChangeToImmediate(getFrameIndexOffset(MF, FrameIndex));
+    return 0;
+  }
+
   if (needsStackRealignment(MF))
     BasePtr = (FrameIndex < 0 ? FramePtr : StackPtr);
   else