Let the strcat optimizer return the pointer to the start of the buffer,
instead of the place where it started to perform the string copy.
- PR3661
- Patch by Benjamin Kramer!
llvm-svn: 68443
diff --git a/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp
index b878e4b..c84c233 100644
--- a/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp
@@ -514,11 +514,11 @@
// Now that we have the destination's length, we must index into the
// destination's pointer to get the actual memcpy destination (end of
// the string .. we're concatenating).
- Dst = B.CreateGEP(Dst, DstLen, "endptr");
+ Value *CpyDst = B.CreateGEP(Dst, DstLen, "endptr");
// We have enough information to now generate the memcpy call to do the
// concatenation for us. Make a memcpy to copy the nul byte with align = 1.
- EmitMemCpy(Dst, Src, ConstantInt::get(TD->getIntPtrType(), Len+1), 1, B);
+ EmitMemCpy(CpyDst, Src, ConstantInt::get(TD->getIntPtrType(), Len+1), 1, B);
return Dst;
}
};
diff --git a/llvm/test/Transforms/SimplifyLibCalls/StrCat.ll b/llvm/test/Transforms/SimplifyLibCalls/StrCat.ll
index a6ef677..89ef4ea 100644
--- a/llvm/test/Transforms/SimplifyLibCalls/StrCat.ll
+++ b/llvm/test/Transforms/SimplifyLibCalls/StrCat.ll
@@ -1,6 +1,9 @@
; Test that the StrCatOptimizer works correctly
+; PR3661
; RUN: llvm-as < %s | opt -simplify-libcalls | llvm-dis | \
; RUN: not grep {call.*strcat}
+; RUN: llvm-as < %s | opt -simplify-libcalls | llvm-dis | \
+; RUN: grep {puts.*%arg1}
@hello = constant [6 x i8] c"hello\00" ; <[6 x i8]*> [#uses=1]
@null = constant [1 x i8] zeroinitializer ; <[1 x i8]*> [#uses=1]