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[InstCombine] Don't blow up in foldICmpWithCastAndCast on vector icmp instructions.

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Summary:
Presently, InstCombiner::foldICmpWithCastAndCast() implicitly assumes that it is
only invoked with icmp instructions of integer type. If that assumption is broken,
and it is called with an icmp of vector type, then it fails (asserts/crashes).

This patch addresses the deficiency. It allows it to simplify
icmp (ptrtoint x), (ptrtoint/c) of vector type into a compare of the inputs,
much as is done when the type is integer.

Reviewers: apilipenko, fedor.sergeev, mkazantsev, anna

Reviewed By: anna

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D44063

llvm-svn: 326730
This commit is contained in:
Daniel Neilson 2018-03-05 18:05:51 +00:00
parent 9741899771
commit 33418abafa
2 changed files with 20 additions and 1 deletions
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9
lib/Transforms/InstCombine/InstCombineCompares.cpp
View File

@ -3408,8 +3408,15 @@ Instruction *InstCombiner::foldICmpWithCastAndCast(ICmpInst &ICmp) {
// Turn icmp (ptrtoint x), (ptrtoint/c) into a compare of the input if the
// integer type is the same size as the pointer type.
const auto& CompatibleSizes = [&](Type* SrcTy, Type* DestTy) -> bool {
if (isa<VectorType>(SrcTy)) {
SrcTy = cast<VectorType>(SrcTy)->getElementType();
DestTy = cast<VectorType>(DestTy)->getElementType();
}
return DL.getPointerTypeSizeInBits(SrcTy) == DestTy->getIntegerBitWidth();
};
if (LHSCI->getOpcode() == Instruction::PtrToInt &&
DL.getPointerTypeSizeInBits(SrcTy) == DestTy->getIntegerBitWidth()) {
CompatibleSizes(SrcTy, DestTy)) {
Value *RHSOp = nullptr;
if (auto *RHSC = dyn_cast<PtrToIntOperator>(ICmp.getOperand(1))) {
Value *RHSCIOp = RHSC->getOperand(0);

12
test/Transforms/InstCombine/icmp.ll
View File

@ -3302,3 +3302,15 @@ define i1 @PR35794(i32* %a) {
ret i1 %cmp
}
; Don't crash by assuming the compared values are integers.
define <2 x i1> @PR36583(<2 x i8*>) {
; CHECK-LABEL: @PR36583(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[RES:%.*]] = icmp eq <2 x i8*> %0, zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[RES]]
;
entry:
%cast = ptrtoint <2 x i8*> %0 to <2 x i64>
%res = icmp eq <2 x i64> %cast, zeroinitializer
ret <2 x i1> %res
}