https://github.com/el-ev updated
https://github.com/llvm/llvm-project/pull/136467
>From 66a876c54233d7bf928b72753485ac2733563b0f Mon Sep 17 00:00:00 2001
From: Iris Shi <0...@owo.li>
Date: Sun, 20 Apr 2025 10:32:29 +0800
Subject: [PATCH] "Recommit "[ConstraintElim] Simplify cmp after
uadd.sat/usub.sat (#135603)"
---
.../Transforms/Scalar/ConstraintElimination.cpp | 16 ++++++++++++++++
.../ConstraintElimination/uadd-usub-sat.ll | 7 ++-----
2 files changed, 18 insertions(+), 5 deletions(-)
diff --git a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
index 8684420b73671..9fd6b067debdf 100644
--- a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
@@ -1139,6 +1139,8 @@ void State::addInfoFor(BasicBlock &BB) {
// when simplifying uses of the min/max intrinsics.
[[fallthrough]];
case Intrinsic::abs:
+ case Intrinsic::uadd_sat:
+ case Intrinsic::usub_sat:
if (!isGuaranteedNotToBePoison(&I))
break;
WorkList.push_back(FactOrCheck::getInstFact(DT.getNode(&BB), &I));
@@ -1896,6 +1898,20 @@ static bool eliminateConstraints(Function &F,
DominatorTree &DT, LoopInfo &LI,
AddFact(Pred, MinMax, MinMax->getRHS());
continue;
}
+ if (auto *USatI = dyn_cast<SaturatingInst>(CB.Inst)) {
+ switch (USatI->getIntrinsicID()) {
+ default:
+ llvm_unreachable("Unexpected intrinsic.");
+ case Intrinsic::uadd_sat:
+ AddFact(ICmpInst::ICMP_UGE, USatI, USatI->getLHS());
+ AddFact(ICmpInst::ICMP_UGE, USatI, USatI->getRHS());
+ break;
+ case Intrinsic::usub_sat:
+ AddFact(ICmpInst::ICMP_ULE, USatI, USatI->getLHS());
+ break;
+ }
+ continue;
+ }
}
Value *A = nullptr, *B = nullptr;
diff --git a/llvm/test/Transforms/ConstraintElimination/uadd-usub-sat.ll
b/llvm/test/Transforms/ConstraintElimination/uadd-usub-sat.ll
index 42bbe67024e58..c19a0548d78b2 100644
--- a/llvm/test/Transforms/ConstraintElimination/uadd-usub-sat.ll
+++ b/llvm/test/Transforms/ConstraintElimination/uadd-usub-sat.ll
@@ -8,9 +8,7 @@ define i1 @uadd_sat_uge(i64 noundef %a, i64 noundef %b) {
; CHECK-LABEL: define i1 @uadd_sat_uge(
; CHECK-SAME: i64 noundef [[A:%.*]], i64 noundef [[B:%.*]]) {
; CHECK-NEXT: [[ADD_SAT:%.*]] = call i64 @llvm.uadd.sat.i64(i64 [[A]], i64
[[B]])
-; CHECK-NEXT: [[CMP1:%.*]] = icmp uge i64 [[ADD_SAT]], [[A]]
-; CHECK-NEXT: [[CMP2:%.*]] = icmp uge i64 [[ADD_SAT]], [[B]]
-; CHECK-NEXT: [[CMP:%.*]] = and i1 [[CMP1]], [[CMP2]]
+; CHECK-NEXT: [[CMP:%.*]] = and i1 true, true
; CHECK-NEXT: ret i1 [[CMP]]
;
%add.sat = call i64 @llvm.uadd.sat.i64(i64 %a, i64 %b)
@@ -24,8 +22,7 @@ define i1 @usub_sat_ule_lhs(i64 noundef %a, i64 noundef %b) {
; CHECK-LABEL: define i1 @usub_sat_ule_lhs(
; CHECK-SAME: i64 noundef [[A:%.*]], i64 noundef [[B:%.*]]) {
; CHECK-NEXT: [[SUB_SAT:%.*]] = call i64 @llvm.usub.sat.i64(i64 [[A]], i64
[[B]])
-; CHECK-NEXT: [[CMP:%.*]] = icmp ule i64 [[SUB_SAT]], [[A]]
-; CHECK-NEXT: ret i1 [[CMP]]
+; CHECK-NEXT: ret i1 true
;
%sub.sat = call i64 @llvm.usub.sat.i64(i64 %a, i64 %b)
%cmp = icmp ule i64 %sub.sat, %a
_______________________________________________
llvm-branch-commits mailing list
llvm-branch-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
