[llvm-commits] [llvm] r48343 - in /llvm/trunk: lib/Transforms/Scalar/GVN.cpp test/Transforms/GVN/2008-03-13-ReturnSlotBitcast.ll

[Owen Anderson]

Author: resistor
Date: Thu Mar 13 17:07:10 2008
New Revision: 48343

URL: http://llvm.org/viewvc/llvm-project?rev=48343&view=rev
Log:
Fix a bug in GVN that Duncan noticed, where we potentially need to insert a 
pointer bitcast when performing return slot optimization.

Added:
    llvm/trunk/test/Transforms/GVN/2008-03-13-ReturnSlotBitcast.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/GVN.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/GVN.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/GVN.cpp?rev=48343&r1=48342&r2=48343&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/GVN.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/GVN.cpp Thu Mar 13 17:07:10 2008
@@ -1171,8 +1171,12 @@
 
   // All the checks have passed, so do the transformation.
   for (unsigned i = 0; i < CS.arg_size(); ++i)
-    if (CS.getArgument(i) == cpySrc)
+    if (CS.getArgument(i) == cpySrc) {
+      if (cpySrc->getType() != cpyDest->getType())
+        cpyDest = CastInst::createPointerCast(cpyDest, cpySrc->getType(),
+                                              cpyDest->getName(), C);
       CS.setArgument(i, cpyDest);
+    }
 
   // Drop any cached information about the call, because we may have changed
   // its dependence information by changing its parameter.

Added: llvm/trunk/test/Transforms/GVN/2008-03-13-ReturnSlotBitcast.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVN/2008-03-13-ReturnSlotBitcast.ll?rev=48343&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/GVN/2008-03-13-ReturnSlotBitcast.ll (added)
+++ llvm/trunk/test/Transforms/GVN/2008-03-13-ReturnSlotBitcast.ll Thu Mar 13 17:07:10 2008
@@ -0,0 +1,19 @@
+; RUN: llvm-as < %s | opt -gvn | llvm-dis | not grep {call.*memcpy.}
+	%a = type { i32 }
+	%b = type { float }
+
+declare void @llvm.memcpy.i32(i8*, i8*, i32, i32) nounwind 
+declare void @g(%a*)
+
+define float @f() {
+entry:
+	%a_var = alloca %a
+	%b_var = alloca %b
+	call void @g(%a *%a_var)
+	%a_i8 = bitcast %a* %a_var to i8*
+	%b_i8 = bitcast %b* %b_var to i8*
+	call void @llvm.memcpy.i32(i8* %b_i8, i8* %a_i8, i32 4, i32 4)
+	%tmp1 = getelementptr %b* %b_var, i32 0, i32 0
+	%tmp2 = load float* %tmp1
+	ret float %tmp2
+}