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Revert "[SimplifyLibCalls] sprintf doesn't copy null bytes" 

The destination buffer that sprintf uses is restrict qualified, we do
not need to worry about derived pointers referenced via format
specifiers.

This reverts commit r267580.

llvm-svn: 267605
This commit is contained in:
David Majnemer 2016-04-26 21:04:47 +00:00
parent ce26eac511
commit abb9f55c80
2 changed files with 5 additions and 7 deletions
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7
llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
View File

@ -1995,10 +1995,9 @@ Value *LibCallSimplifier::optimizeSPrintFString(CallInst *CI, IRBuilder<> &B) {
Value *Len = emitStrLen(CI->getArgOperand(2), B, DL, TLI);
if (!Len)
return nullptr;
B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(2), Len, 1);
Value *PtrToNullByte =
B.CreateGEP(B.getInt8Ty(), CI->getArgOperand(0), Len, "nul");
B.CreateStore(B.getInt8(0), PtrToNullByte);
Value *IncLen =
B.CreateAdd(Len, ConstantInt::get(Len->getType(), 1), "leninc");
B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(2), IncLen, 1);
// The sprintf result is the unincremented number of bytes in the string.
return B.CreateIntCast(Len, CI->getType(), false);

5
llvm/test/Transforms/InstCombine/sprintf-1.ll
View File

@ -65,9 +65,8 @@ define void @test_simplify5(i8* %dst, i8* %str) {
%fmt = getelementptr [3 x i8], [3 x i8]* @percent_s, i32 0, i32 0
call i32 (i8*, i8*, ...) @sprintf(i8* %dst, i8* %fmt, i8* %str)
; CHECK-NEXT: [[STRLEN:%[a-z0-9]+]] = call i32 @strlen(i8* %str)
; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %str, i32 [[STRLEN]], i32 1, i1 false)
; CHECK-NEXT: [[NUL:%[a-z0-9]+]] = getelementptr i8, i8* %dst, i32 [[STRLEN]]
; CHECK-NEXT: store i8 0, i8* [[NUL]], align 1
; CHECK-NEXT: [[LENINC:%[a-z0-9]+]] = add i32 [[STRLEN]], 1
; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %str, i32 [[LENINC]], i32 1, i1 false)
ret void
; CHECK-NEXT: ret void
}