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Subtraction is not commutative. Fixes PR23212!

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234780 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2015-04-13 19:17:37 +00:00
parent 7bea98826a
commit d4b4e3e20f
3 changed files with 19 additions and 7 deletions
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13
lib/Transforms/InstCombine/InstCombineCalls.cpp
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@ -416,12 +416,10 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
}
break;
case Intrinsic::uadd_with_overflow: // FALLTHROUGH
case Intrinsic::sadd_with_overflow: // FALLTHROUGH
case Intrinsic::usub_with_overflow: // FALLTHROUGH
case Intrinsic::ssub_with_overflow: // FALLTHROUGH
case Intrinsic::umul_with_overflow: // FALLTHROUGH
case Intrinsic::smul_with_overflow: {
case Intrinsic::uadd_with_overflow:
case Intrinsic::sadd_with_overflow:
case Intrinsic::umul_with_overflow:
case Intrinsic::smul_with_overflow:
if (isa<Constant>(II->getArgOperand(0)) &&
!isa<Constant>(II->getArgOperand(1))) {
// Canonicalize constants into the RHS.
@ -430,7 +428,10 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
II->setArgOperand(1, LHS);
return II;
}
[[clang::fallthrough]];
case Intrinsic::usub_with_overflow:
case Intrinsic::ssub_with_overflow: {
OverflowCheckFlavor OCF =
IntrinsicIDToOverflowCheckFlavor(II->getIntrinsicID());
assert(OCF != OCF_INVALID && "unexpected!");

3
lib/Transforms/InstCombine/InstCombineCompares.cpp
View File

@ -2112,7 +2112,8 @@ static Instruction *ProcessUGT_ADDCST_ADD(ICmpInst &I, Value *A, Value *B,
bool InstCombiner::OptimizeOverflowCheck(OverflowCheckFlavor OCF, Value *LHS,
Value *RHS, Instruction &OrigI,
Value *&Result, Constant *&Overflow) {
assert(!(isa<Constant>(LHS) && !isa<Constant>(RHS)) &&
assert((!OrigI.isCommutative() ||
!(isa<Constant>(LHS) && !isa<Constant>(RHS))) &&
"call with a constant RHS if possible!");
auto SetResult = [&](Value *OpResult, Constant *OverflowVal, bool ReuseName) {

10
test/Transforms/InstCombine/intrinsics.ll
View File

@ -407,3 +407,13 @@ entry:
%obit = extractvalue %ov.result.32 %t, 1
ret i1 %obit
}
define %ov.result.32 @ssubtest_reorder(i8 %a) {
%A = sext i8 %a to i32
%x = call %ov.result.32 @llvm.ssub.with.overflow.i32(i32 0, i32 %A)
ret %ov.result.32 %x
; CHECK-LABEL: @ssubtest_reorder
; CHECK: %x = sub nsw i32 0, %A
; CHECK-NEXT: %1 = insertvalue %ov.result.32 { i32 undef, i1 false }, i32 %x, 0
; CHECK-NEXT: ret %ov.result.32 %1
}