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[SLC] Optimize mempcpy_chk to mempcpy 

As reported in PR46735:

void* f(void *d, const void *s, size_t l)
{
    return __builtin___mempcpy_chk(d, s, l, __builtin_object_size(d, 0));
}

This can be optimized to `return mempcpy(d, s, l);`.

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D86019
This commit is contained in:
Dávid Bolvanský 2020-10-05 22:16:59 +02:00
parent a506a66bd9
commit 3f1fd59de3
7 changed files with 56 additions and 0 deletions
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3
llvm/include/llvm/Analysis/TargetLibraryInfo.def
View File

@ -366,6 +366,9 @@ TLI_DEFINE_STRING_INTERNAL("__memcpy_chk")
/// void *__memmove_chk(void *s1, const void *s2, size_t n, size_t s1size);
TLI_DEFINE_ENUM_INTERNAL(memmove_chk)
TLI_DEFINE_STRING_INTERNAL("__memmove_chk")
/// void *__mempcpy_chk(void *s1, const void *s2, size_t n, size_t s1size);
TLI_DEFINE_ENUM_INTERNAL(mempcpy_chk)
TLI_DEFINE_STRING_INTERNAL("__mempcpy_chk")
/// void *__memset_chk(void *s, char v, size_t n, size_t s1size);
TLI_DEFINE_ENUM_INTERNAL(memset_chk)
TLI_DEFINE_STRING_INTERNAL("__memset_chk")

4
llvm/include/llvm/Transforms/Utils/BuildLibCalls.h
View File

@ -96,6 +96,10 @@ namespace llvm {
IRBuilderBase &B, const DataLayout &DL,
const TargetLibraryInfo *TLI);
/// Emit a call to the mempcpy function.
Value *emitMemPCpy(Value *Dst, Value *Src, Value *Len, IRBuilderBase &B,
const DataLayout &DL, const TargetLibraryInfo *TLI);
/// Emit a call to the memchr function. This assumes that Ptr is a pointer,
/// Val is an i32 value, and Len is an 'intptr_t' value.
Value *emitMemChr(Value *Ptr, Value *Val, Value *Len, IRBuilderBase &B,

1
llvm/include/llvm/Transforms/Utils/SimplifyLibCalls.h
View File

@ -59,6 +59,7 @@ private:
Value *optimizeStrpCpyChk(CallInst *CI, IRBuilderBase &B, LibFunc Func);
Value *optimizeStrpNCpyChk(CallInst *CI, IRBuilderBase &B, LibFunc Func);
Value *optimizeStrLenChk(CallInst *CI, IRBuilderBase &B);
Value *optimizeMemPCpyChk(CallInst *CI, IRBuilderBase &B);
Value *optimizeMemCCpyChk(CallInst *CI, IRBuilderBase &B);
Value *optimizeSNPrintfChk(CallInst *CI, IRBuilderBase &B);
Value *optimizeSPrintfChk(CallInst *CI,IRBuilderBase &B);

1
llvm/lib/Analysis/TargetLibraryInfo.cpp
View File

@ -847,6 +847,7 @@ bool TargetLibraryInfoImpl::isValidProtoForLibFunc(const FunctionType &FTy,
return (NumParams >= 2 && FTy.getParamType(1)->isPointerTy());
case LibFunc_memcpy_chk:
case LibFunc_mempcpy_chk:
case LibFunc_memmove_chk:
--NumParams;
if (!IsSizeTTy(FTy.getParamType(NumParams)))

9
llvm/lib/Transforms/Utils/BuildLibCalls.cpp
View File

@ -1076,6 +1076,15 @@ Value *llvm::emitMemCpyChk(Value *Dst, Value *Src, Value *Len, Value *ObjSize,
return CI;
}
Value *llvm::emitMemPCpy(Value *Dst, Value *Src, Value *Len, IRBuilderBase &B,
const DataLayout &DL, const TargetLibraryInfo *TLI) {
LLVMContext &Context = B.GetInsertBlock()->getContext();
return emitLibCall(
LibFunc_mempcpy, B.getInt8PtrTy(),
{B.getInt8PtrTy(), B.getInt8PtrTy(), DL.getIntPtrType(Context)},
{Dst, Src, Len}, B, TLI);
}
Value *llvm::emitMemChr(Value *Ptr, Value *Val, Value *Len, IRBuilderBase &B,
const DataLayout &DL, const TargetLibraryInfo *TLI) {
LLVMContext &Context = B.GetInsertBlock()->getContext();

15
llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
View File

@ -3292,6 +3292,19 @@ Value *FortifiedLibCallSimplifier::optimizeMemSetChk(CallInst *CI,
return nullptr;
}
Value *FortifiedLibCallSimplifier::optimizeMemPCpyChk(CallInst *CI,
IRBuilderBase &B) {
const DataLayout &DL = CI->getModule()->getDataLayout();
if (isFortifiedCallFoldable(CI, 3, 2))
if (Value *Call = emitMemPCpy(CI->getArgOperand(0), CI->getArgOperand(1),
CI->getArgOperand(2), B, DL, TLI)) {
CallInst *NewCI = cast<CallInst>(Call);
NewCI->setAttributes(CI->getAttributes());
return NewCI;
}
return nullptr;
}
Value *FortifiedLibCallSimplifier::optimizeStrpCpyChk(CallInst *CI,
IRBuilderBase &B,
LibFunc Func) {
@ -3481,6 +3494,8 @@ Value *FortifiedLibCallSimplifier::optimizeCall(CallInst *CI,
switch (Func) {
case LibFunc_memcpy_chk:
return optimizeMemCpyChk(CI, Builder);
case LibFunc_mempcpy_chk:
return optimizeMemPCpyChk(CI, Builder);
case LibFunc_memmove_chk:
return optimizeMemMoveChk(CI, Builder);
case LibFunc_memset_chk:

23
llvm/test/Transforms/InstCombine/fortify-folding.ll
View File

@ -31,6 +31,28 @@ define i8* @test_not_memccpy() {
ret i8* %ret
}
define i8* @test_mempcpy() {
; CHECK-LABEL: @test_mempcpy(
; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 1 dereferenceable(15) getelementptr inbounds ([60 x i8], [60 x i8]* @a, i64 0, i64 0), i8* nonnull align 1 dereferenceable(15) getelementptr inbounds ([60 x i8], [60 x i8]* @b, i64 0, i64 0), i64 15, i1 false)
; CHECK-NEXT: ret i8* getelementptr inbounds ([60 x i8], [60 x i8]* @a, i64 0, i64 15)
;
%dst = getelementptr inbounds [60 x i8], [60 x i8]* @a, i32 0, i32 0
%src = getelementptr inbounds [60 x i8], [60 x i8]* @b, i32 0, i32 0
%ret = call i8* @__mempcpy_chk(i8* %dst, i8* %src, i64 15, i64 -1)
ret i8* %ret
}
define i8* @test_not_mempcpy() {
; CHECK-LABEL: @test_not_mempcpy(
; CHECK-NEXT: [[RET:%.*]] = call i8* @__mempcpy_chk(i8* getelementptr inbounds ([60 x i8], [60 x i8]* @a, i64 0, i64 0), i8* getelementptr inbounds ([60 x i8], [60 x i8]* @b, i64 0, i64 0), i64 60, i64 59)
; CHECK-NEXT: ret i8* [[RET]]
;
%dst = getelementptr inbounds [60 x i8], [60 x i8]* @a, i32 0, i32 0
%src = getelementptr inbounds [60 x i8], [60 x i8]* @b, i32 0, i32 0
%ret = call i8* @__mempcpy_chk(i8* %dst, i8* %src, i64 60, i64 59)
ret i8* %ret
}
define i32 @test_snprintf() {
; CHECK-LABEL: @test_snprintf(
; CHECK-NEXT: [[SNPRINTF:%.*]] = call i32 (i8*, i64, i8*, ...) @snprintf(i8* nonnull dereferenceable(1) getelementptr inbounds ([60 x i8], [60 x i8]* @a, i64 0, i64 0), i64 60, i8* getelementptr inbounds ([60 x i8], [60 x i8]* @b, i64 0, i64 0))
@ -219,6 +241,7 @@ define i32 @test_not_vsprintf() {
ret i32 %ret
}
declare i8* @__mempcpy_chk(i8*, i8*, i64, i64)
declare i8* @__memccpy_chk(i8*, i8*, i32, i64, i64)
declare i32 @__snprintf_chk(i8*, i64, i32, i64, i8*, ...)
declare i32 @__sprintf_chk(i8*, i32, i64, i8*, ...)