Fix a bug in memcpyopt where the memcpy-memcpy transform was never being applied because

we were checking for it in the wrong order.  This caused a miscompilation because the
return slot optimization assumes that the call it is dealing with is NOT a memcpy.

llvm-svn: 50444

1 files changed, 6 insertions, 4 deletions

diff --git a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
index d2723ab342b..9a39c8fd29e 100644
--- a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
+++ b/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
@@ -615,10 +615,12 @@ bool MemCpyOpt::processMemCpy(MemCpyInst* M) {
   if (dep == MemoryDependenceAnalysis::None ||
       dep == MemoryDependenceAnalysis::NonLocal)
     return false;
-  else if (CallInst* C = dyn_cast<CallInst>(dep))
-    return performCallSlotOptzn(M, C);
-  else if (!isa<MemCpyInst>(dep))
-    return false;
+  else if (!isa<MemCpyInst>(dep)) {
+    if (CallInst* C = dyn_cast<CallInst>(dep))
+      return performCallSlotOptzn(M, C);
+    else
+      return false;
+  }
   
   MemCpyInst* MDep = cast<MemCpyInst>(dep);