If known DebugLocs do not match then two DBG_VALUE machine instructions are not identical. For example,

        DBG_VALUE 3.310000e+02, 0, !"ds"; dbg:sse.stepfft.c:138:18 @[ sse.stepfft.c:32:10 ]
        DBG_VALUE 3.310000e+02, 0, !"ds"; dbg:sse.stepfft.c:138:18 @[ sse.stepfft.c:31:10 ]

These two MIs represent identical value, 3.31...,  for one variable, ds, but they are not identical because the represent two separate instances of inlined variable "ds". 

llvm-svn: 134620

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp
index f490713e720..143a29b08a1 100644
--- a/llvm/lib/CodeGen/MachineInstr.cpp
+++ b/llvm/lib/CodeGen/MachineInstr.cpp
@@ -802,6 +802,11 @@ bool MachineInstr::isIdenticalTo(const MachineInstr *Other,
         return false;
     }
   }
+  // If DebugLoc does not match then two dbg.values are not identical.
+  if (isDebugValue())
+    if (!getDebugLoc().isUnknown() && !Other->getDebugLoc().isUnknown()
+        && getDebugLoc() != Other->getDebugLoc())
+      return false;
   return true;
 }