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[InstCombine] stpcpy(d,s) -> strcpy(d,s) if the result is not used

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This commit is contained in:
Dávid Bolvanský 2021-09-05 12:12:07 +02:00
parent 7801d7963d
commit 9c476172b9
4 changed files with 12 additions and 7 deletions
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2
llvm/lib/Transforms/Utils/BuildLibCalls.cpp
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@ -1268,7 +1268,7 @@ Value *llvm::emitStrNCmp(Value *Ptr1, Value *Ptr2, Value *Len, IRBuilderBase &B,
Value *llvm::emitStrCpy(Value *Dst, Value *Src, IRBuilderBase &B,
const TargetLibraryInfo *TLI) {
Type *I8Ptr = B.getInt8PtrTy();
Type *I8Ptr = Dst->getType();
return emitLibCall(LibFunc_strcpy, I8Ptr, {I8Ptr, I8Ptr},
{castToCStr(Dst, B), castToCStr(Src, B)}, B, TLI);
}

5
llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
View file

@ -517,6 +517,11 @@ Value *LibCallSimplifier::optimizeStrCpy(CallInst *CI, IRBuilderBase &B) {
Value *LibCallSimplifier::optimizeStpCpy(CallInst *CI, IRBuilderBase &B) {
Function *Callee = CI->getCalledFunction();
Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
// stpcpy(d,s) -> strcpy(d,s) if the result is not used.
if (CI->use_empty())
return emitStrCpy(Dst, Src, B, TLI);
if (Dst == Src) { // stpcpy(x,x) -> x+strlen(x)
Value *StrLen = emitStrLen(Src, B, DL, TLI);
return StrLen ? B.CreateInBoundsGEP(B.getInt8Ty(), Dst, StrLen) : nullptr;

2
llvm/test/Transforms/InstCombine/stpcpy-1.ll
View file

@ -38,7 +38,7 @@ define i8* @test_simplify2() {
define void @test_simplify3(i8* %dst) {
; CHECK-LABEL: @test_simplify3(
; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* noundef nonnull align 1 dereferenceable(80) [[DST:%.*]], i8* noundef nonnull align 1 dereferenceable(6) getelementptr inbounds ([6 x i8], [6 x i8]* @hello, i32 0, i32 0), i32 6, i1 false)
; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* noundef nonnull align 1 dereferenceable(6) [[DST:%.*]], i8* noundef nonnull align 1 dereferenceable(6) getelementptr inbounds ([6 x i8], [6 x i8]* @hello, i32 0, i32 0), i32 6, i1 false)
; CHECK-NEXT: ret void
;
%src = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0

10
llvm/test/Transforms/InstCombine/strcpy-nonzero-as.ll
View file

@ -13,7 +13,7 @@ declare i8 addrspace(200)* @stpncpy(i8 addrspace(200)*, i8 addrspace(200)*, i64)
define void @test_strcpy_to_memcpy(i8 addrspace(200)* %dst) addrspace(200) nounwind {
; CHECK-LABEL: define {{[^@]+}}@test_strcpy_to_memcpy
; CHECK-SAME: (i8 addrspace(200)* [[DST:%.*]]) addrspace(200) [[ATTR0:#.*]] {
; CHECK-SAME: (i8 addrspace(200)* [[DST:%.*]]) addrspace(200) #[[ATTR1:[0-9]+]] {
; CHECK-NEXT: entry:
; CHECK-NEXT: call addrspace(200) void @llvm.memcpy.p200i8.p200i8.i64(i8 addrspace(200)* noundef align 1 dereferenceable(17) [[DST]], i8 addrspace(200)* noundef align 1 dereferenceable(17) getelementptr inbounds ([17 x i8], [17 x i8] addrspace(200)* @str, i64 0, i64 0), i64 17, i1 false)
; CHECK-NEXT: ret void
@ -25,9 +25,9 @@ entry:
define void @test_stpcpy_to_memcpy(i8 addrspace(200)* %dst) addrspace(200) nounwind {
; CHECK-LABEL: define {{[^@]+}}@test_stpcpy_to_memcpy
; CHECK-SAME: (i8 addrspace(200)* [[DST:%.*]]) addrspace(200) [[ATTR0]] {
; CHECK-SAME: (i8 addrspace(200)* [[DST:%.*]]) addrspace(200) #[[ATTR1]] {
; CHECK-NEXT: entry:
; CHECK-NEXT: call addrspace(200) void @llvm.memcpy.p200i8.p200i8.i128(i8 addrspace(200)* noundef align 1 dereferenceable(17) [[DST]], i8 addrspace(200)* noundef align 1 dereferenceable(17) getelementptr inbounds ([17 x i8], [17 x i8] addrspace(200)* @str, i64 0, i64 0), i128 17, i1 false)
; CHECK-NEXT: call addrspace(200) void @llvm.memcpy.p200i8.p200i8.i64(i8 addrspace(200)* noundef align 1 dereferenceable(17) [[DST]], i8 addrspace(200)* noundef align 1 dereferenceable(17) getelementptr inbounds ([17 x i8], [17 x i8] addrspace(200)* @str, i64 0, i64 0), i64 17, i1 false)
; CHECK-NEXT: ret void
;
entry:
@ -37,7 +37,7 @@ entry:
define void @test_strncpy_to_memcpy(i8 addrspace(200)* %dst) addrspace(200) nounwind {
; CHECK-LABEL: define {{[^@]+}}@test_strncpy_to_memcpy
; CHECK-SAME: (i8 addrspace(200)* [[DST:%.*]]) addrspace(200) [[ATTR0]] {
; CHECK-SAME: (i8 addrspace(200)* [[DST:%.*]]) addrspace(200) #[[ATTR1]] {
; CHECK-NEXT: entry:
; CHECK-NEXT: call addrspace(200) void @llvm.memcpy.p200i8.p200i8.i128(i8 addrspace(200)* noundef align 1 dereferenceable(17) [[DST]], i8 addrspace(200)* noundef align 1 dereferenceable(17) getelementptr inbounds ([17 x i8], [17 x i8] addrspace(200)* @str, i64 0, i64 0), i128 17, i1 false)
; CHECK-NEXT: ret void
@ -50,7 +50,7 @@ entry:
; Note: stpncpy is not handled by SimplifyLibcalls yet, so this should not be changed.
define void @test_stpncpy_to_memcpy(i8 addrspace(200)* %dst) addrspace(200) nounwind {
; CHECK-LABEL: define {{[^@]+}}@test_stpncpy_to_memcpy
; CHECK-SAME: (i8 addrspace(200)* [[DST:%.*]]) addrspace(200) [[ATTR0]] {
; CHECK-SAME: (i8 addrspace(200)* [[DST:%.*]]) addrspace(200) #[[ATTR1]] {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[CALL:%.*]] = call addrspace(200) i8 addrspace(200)* @stpncpy(i8 addrspace(200)* [[DST]], i8 addrspace(200)* getelementptr inbounds ([17 x i8], [17 x i8] addrspace(200)* @str, i64 0, i64 0), i64 17)
; CHECK-NEXT: ret void