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Let the strcat optimizer return the pointer to the start of the buffer,

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instead of the place where it started to perform the string copy.

- PR3661
- Patch by Benjamin Kramer!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68443 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Ed Schouten 2009-04-06 13:06:48 +00:00
parent cae1b628a7
commit b5e0a96a8d
2 changed files with 5 additions and 2 deletions
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4
lib/Transforms/Scalar/SimplifyLibCalls.cpp
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@ -514,11 +514,11 @@ struct VISIBILITY_HIDDEN StrCatOpt : public LibCallOptimization {
// 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;
}
};

3
test/Transforms/SimplifyLibCalls/StrCat.ll
View File

@ -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]