[IR] Add WithOverflowInst class
This adds a WithOverflowInst class with a few helper methods to get
the underlying binop, signedness and nowrap type and makes use of it
where sensible. There will be two more uses in D60650/D60656.
The refactorings are all NFC, though I left some TODOs where things
could be improved. In particular we have two places where add/sub are
handled but mul isn't.
Differential Revision: https://reviews.llvm.org/D60668
llvm-svn: 358512
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 350eb3d..01b4019 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -4575,52 +4575,21 @@
if (EVI->getNumIndices() != 1 || EVI->getIndices()[0] != 0)
break;
- auto *CI = dyn_cast<CallInst>(EVI->getAggregateOperand());
- if (!CI)
+ auto *WO = dyn_cast<WithOverflowInst>(EVI->getAggregateOperand());
+ if (!WO)
break;
- if (auto *F = CI->getCalledFunction())
- switch (F->getIntrinsicID()) {
- case Intrinsic::sadd_with_overflow:
- case Intrinsic::uadd_with_overflow:
- if (!isOverflowIntrinsicNoWrap(cast<IntrinsicInst>(CI), DT))
- return BinaryOp(Instruction::Add, CI->getArgOperand(0),
- CI->getArgOperand(1));
+ Instruction::BinaryOps BinOp = WO->getBinaryOp();
+ bool Signed = WO->isSigned();
+ // TODO: Should add nuw/nsw flags for mul as well.
+ if (BinOp == Instruction::Mul || !isOverflowIntrinsicNoWrap(WO, DT))
+ return BinaryOp(BinOp, WO->getLHS(), WO->getRHS());
- // Now that we know that all uses of the arithmetic-result component of
- // CI are guarded by the overflow check, we can go ahead and pretend
- // that the arithmetic is non-overflowing.
- if (F->getIntrinsicID() == Intrinsic::sadd_with_overflow)
- return BinaryOp(Instruction::Add, CI->getArgOperand(0),
- CI->getArgOperand(1), /* IsNSW = */ true,
- /* IsNUW = */ false);
- else
- return BinaryOp(Instruction::Add, CI->getArgOperand(0),
- CI->getArgOperand(1), /* IsNSW = */ false,
- /* IsNUW*/ true);
- case Intrinsic::ssub_with_overflow:
- case Intrinsic::usub_with_overflow:
- if (!isOverflowIntrinsicNoWrap(cast<IntrinsicInst>(CI), DT))
- return BinaryOp(Instruction::Sub, CI->getArgOperand(0),
- CI->getArgOperand(1));
-
- // The same reasoning as sadd/uadd above.
- if (F->getIntrinsicID() == Intrinsic::ssub_with_overflow)
- return BinaryOp(Instruction::Sub, CI->getArgOperand(0),
- CI->getArgOperand(1), /* IsNSW = */ true,
- /* IsNUW = */ false);
- else
- return BinaryOp(Instruction::Sub, CI->getArgOperand(0),
- CI->getArgOperand(1), /* IsNSW = */ false,
- /* IsNUW = */ true);
- case Intrinsic::smul_with_overflow:
- case Intrinsic::umul_with_overflow:
- return BinaryOp(Instruction::Mul, CI->getArgOperand(0),
- CI->getArgOperand(1));
- default:
- break;
- }
- break;
+ // Now that we know that all uses of the arithmetic-result component of
+ // CI are guarded by the overflow check, we can go ahead and pretend
+ // that the arithmetic is non-overflowing.
+ return BinaryOp(BinOp, WO->getLHS(), WO->getRHS(),
+ /* IsNSW = */ Signed, /* IsNUW = */ !Signed);
}
default:
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 4bb4d30..9c7b0fa 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -4206,23 +4206,12 @@
return mapOverflowResult(LHSRange.signedSubMayOverflow(RHSRange));
}
-bool llvm::isOverflowIntrinsicNoWrap(const IntrinsicInst *II,
+bool llvm::isOverflowIntrinsicNoWrap(const WithOverflowInst *WO,
const DominatorTree &DT) {
-#ifndef NDEBUG
- auto IID = II->getIntrinsicID();
- assert((IID == Intrinsic::sadd_with_overflow ||
- IID == Intrinsic::uadd_with_overflow ||
- IID == Intrinsic::ssub_with_overflow ||
- IID == Intrinsic::usub_with_overflow ||
- IID == Intrinsic::smul_with_overflow ||
- IID == Intrinsic::umul_with_overflow) &&
- "Not an overflow intrinsic!");
-#endif
-
SmallVector<const BranchInst *, 2> GuardingBranches;
SmallVector<const ExtractValueInst *, 2> Results;
- for (const User *U : II->users()) {
+ for (const User *U : WO->users()) {
if (const auto *EVI = dyn_cast<ExtractValueInst>(U)) {
assert(EVI->getNumIndices() == 1 && "Obvious from CI's type");