https://github.com/alexander-shaposhnikov updated
https://github.com/llvm/llvm-project/pull/73189
>From a9e76a878edc8bc9cb81b8aa169bbbc467d32026 Mon Sep 17 00:00:00 2001
From: Alexander Shaposhnikov <ashaposhni...@google.com>
Date: Thu, 23 Nov 2023 00:37:08 +0000
Subject: [PATCH] [ConstraintElim] Add a fact implied by llvm.abs
---
.../Scalar/ConstraintElimination.cpp | 10 +++++++
.../Transforms/ConstraintElimination/abs.ll | 26 +++++++++++++++++++
2 files changed, 36 insertions(+)
create mode 100644 llvm/test/Transforms/ConstraintElimination/abs.ll
diff --git a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
index 7aadd810c1da3..59aaa677ccbf9 100644
--- a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
@@ -995,6 +995,11 @@ void State::addInfoFor(BasicBlock &BB) {
continue;
}
+ if (match(&I, m_Intrinsic<Intrinsic::abs>())) {
+ WorkList.push_back(FactOrCheck::getInstFact(DT.getNode(&BB), &I));
+ continue;
+ }
+
Value *A, *B;
CmpInst::Predicate Pred;
// For now, just handle assumes with a single compare as condition.
@@ -1629,6 +1634,11 @@ static bool eliminateConstraints(Function &F,
DominatorTree &DT, LoopInfo &LI,
ICmpInst::Predicate Pred;
if (!CB.isConditionFact()) {
+ if (Value *X; match(CB.Inst, m_Intrinsic<Intrinsic::abs>(m_Value(X)))) {
+ AddFact(CmpInst::ICMP_SGE, CB.Inst, X);
+ continue;
+ }
+
if (auto *MinMax = dyn_cast<MinMaxIntrinsic>(CB.Inst)) {
Pred = ICmpInst::getNonStrictPredicate(MinMax->getPredicate());
AddFact(Pred, MinMax, MinMax->getLHS());
diff --git a/llvm/test/Transforms/ConstraintElimination/abs.ll
b/llvm/test/Transforms/ConstraintElimination/abs.ll
new file mode 100644
index 0000000000000..1cf56c6e37a8c
--- /dev/null
+++ b/llvm/test/Transforms/ConstraintElimination/abs.ll
@@ -0,0 +1,26 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
UTC_ARGS: --version 4
+; RUN: opt -passes=constraint-elimination -S %s | FileCheck %s
+
+define i1 @abs_false(i32 %arg) {
+; CHECK-LABEL: define i1 @abs_false(
+; CHECK-SAME: i32 [[ARG:%.*]]) {
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[ARG]], i1
false)
+; CHECK-NEXT: ret i1 true
+;
+ %abs = tail call i32 @llvm.abs.i32(i32 %arg, i1 false)
+ %cmp = icmp sge i32 %abs, %arg
+ ret i1 %cmp
+}
+
+define i1 @abs_true(i32 %arg) {
+; CHECK-LABEL: define i1 @abs_true(
+; CHECK-SAME: i32 [[ARG:%.*]]) {
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[ARG]], i1
true)
+; CHECK-NEXT: ret i1 true
+;
+ %abs = tail call i32 @llvm.abs.i32(i32 %arg, i1 true)
+ %cmp = icmp sge i32 %abs, %arg
+ ret i1 %cmp
+}
+
+declare i32 @llvm.abs.i32(i32, i1 immarg)
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