[llvm] bc9c2be - [ConstraintElim] Simplify `MinMaxIntrinsic` (#75306)
via llvm-commits
llvm-commits at lists.llvm.org
Sun Feb 4 05:07:44 PST 2024
Author: Yingwei Zheng
Date: 2024-02-04T21:07:40+08:00
New Revision: bc9c2be3577c58d3daabff995360bd9bea44b0b9
URL: https://github.com/llvm/llvm-project/commit/bc9c2be3577c58d3daabff995360bd9bea44b0b9
DIFF: https://github.com/llvm/llvm-project/commit/bc9c2be3577c58d3daabff995360bd9bea44b0b9.diff
LOG: [ConstraintElim] Simplify `MinMaxIntrinsic` (#75306)
This patch replaces min/max intrinsic with one of its operands if
possible.
Alive2: https://alive2.llvm.org/ce/z/LoHfYf
Fixes #75155.
Added:
Modified:
llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
llvm/test/Transforms/ConstraintElimination/minmax.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
index ae8e2292519cb..97cf5ebe3ca06 100644
--- a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
@@ -1065,6 +1065,9 @@ void State::addInfoFor(BasicBlock &BB) {
case Intrinsic::umax:
case Intrinsic::smin:
case Intrinsic::smax:
+ // TODO: handle llvm.abs as well
+ WorkList.push_back(
+ FactOrCheck::getCheck(DT.getNode(&BB), cast<CallInst>(&I)));
// TODO: Check if it is possible to instead only added the min/max facts
// when simplifying uses of the min/max intrinsics.
if (!isGuaranteedNotToBePoison(&I))
@@ -1395,6 +1398,26 @@ static bool checkAndReplaceCondition(
return false;
}
+static bool checkAndReplaceMinMax(MinMaxIntrinsic *MinMax, ConstraintInfo &Info,
+ SmallVectorImpl<Instruction *> &ToRemove) {
+ auto ReplaceMinMaxWithOperand = [&](MinMaxIntrinsic *MinMax, bool UseLHS) {
+ // TODO: generate reproducer for min/max.
+ MinMax->replaceAllUsesWith(MinMax->getOperand(UseLHS ? 0 : 1));
+ ToRemove.push_back(MinMax);
+ return true;
+ };
+
+ ICmpInst::Predicate Pred =
+ ICmpInst::getNonStrictPredicate(MinMax->getPredicate());
+ if (auto ImpliedCondition = checkCondition(
+ Pred, MinMax->getOperand(0), MinMax->getOperand(1), MinMax, Info))
+ return ReplaceMinMaxWithOperand(MinMax, *ImpliedCondition);
+ if (auto ImpliedCondition = checkCondition(
+ Pred, MinMax->getOperand(1), MinMax->getOperand(0), MinMax, Info))
+ return ReplaceMinMaxWithOperand(MinMax, !*ImpliedCondition);
+ return false;
+}
+
static void
removeEntryFromStack(const StackEntry &E, ConstraintInfo &Info,
Module *ReproducerModule,
@@ -1695,6 +1718,8 @@ static bool eliminateConstraints(Function &F, DominatorTree &DT, LoopInfo &LI,
ReproducerCondStack, DFSInStack);
}
Changed |= Simplified;
+ } else if (auto *MinMax = dyn_cast<MinMaxIntrinsic>(Inst)) {
+ Changed |= checkAndReplaceMinMax(MinMax, Info, ToRemove);
}
continue;
}
diff --git a/llvm/test/Transforms/ConstraintElimination/minmax.ll b/llvm/test/Transforms/ConstraintElimination/minmax.ll
index 82b932f14c4ff..68513ea10ad0f 100644
--- a/llvm/test/Transforms/ConstraintElimination/minmax.ll
+++ b/llvm/test/Transforms/ConstraintElimination/minmax.ll
@@ -343,6 +343,264 @@ end:
ret i32 0
}
+; Test from PR75155
+define i32 @simplify_slt_smax_val(i32 %a, i32 %b) {
+; CHECK-LABEL: define i32 @simplify_slt_smax_val
+; CHECK-SAME: (i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT: start:
+; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[A]], [[B]]
+; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK: then:
+; CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[A]], 1
+; CHECK-NEXT: ret i32 [[B]]
+; CHECK: else:
+; CHECK-NEXT: ret i32 -1
+;
+start:
+ %cmp = icmp slt i32 %a, %b
+ br i1 %cmp, label %then, label %else
+then:
+ %add = add nsw i32 %a, 1
+ %max = call i32 @llvm.smax.i32(i32 %b, i32 %add)
+ ret i32 %max
+else:
+ ret i32 -1
+}
+
+define i32 @simplify_slt_smax_val_commuted(i32 %a, i32 %b) {
+; CHECK-LABEL: define i32 @simplify_slt_smax_val_commuted
+; CHECK-SAME: (i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT: start:
+; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[A]], [[B]]
+; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK: then:
+; CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[A]], 1
+; CHECK-NEXT: ret i32 [[B]]
+; CHECK: else:
+; CHECK-NEXT: ret i32 -1
+;
+start:
+ %cmp = icmp slt i32 %a, %b
+ br i1 %cmp, label %then, label %else
+then:
+ %add = add nsw i32 %a, 1
+ %max = call i32 @llvm.smax.i32(i32 %add, i32 %b)
+ ret i32 %max
+else:
+ ret i32 -1
+}
+
+define i32 @simplify_slt_smax_val_at_use(i32 %a, i32 %b) {
+; CHECK-LABEL: define i32 @simplify_slt_smax_val_at_use
+; CHECK-SAME: (i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT: start:
+; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[A]], [[B]]
+; CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[A]], 1
+; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.smax.i32(i32 [[B]], i32 [[ADD]])
+; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK: then:
+; CHECK-NEXT: ret i32 [[MAX]]
+; CHECK: else:
+; CHECK-NEXT: ret i32 -1
+;
+start:
+ %cmp = icmp slt i32 %a, %b
+ %add = add nsw i32 %a, 1
+ %max = call i32 @llvm.smax.i32(i32 %b, i32 %add)
+ br i1 %cmp, label %then, label %else
+then:
+ ret i32 %max
+else:
+ ret i32 -1
+}
+
+define i32 @simplify_sgt_smax_val(i32 %a, i32 %b) {
+; CHECK-LABEL: define i32 @simplify_sgt_smax_val
+; CHECK-SAME: (i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT: start:
+; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[A]], [[B]]
+; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK: then:
+; CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[A]], 1
+; CHECK-NEXT: ret i32 [[ADD]]
+; CHECK: else:
+; CHECK-NEXT: ret i32 -1
+;
+start:
+ %cmp = icmp sgt i32 %a, %b
+ br i1 %cmp, label %then, label %else
+then:
+ %add = add nsw i32 %a, 1
+ %max = call i32 @llvm.smax.i32(i32 %b, i32 %add)
+ ret i32 %max
+else:
+ ret i32 -1
+}
+
+define i32 @simplify_sle_smax_val(i32 %a, i32 %b) {
+; CHECK-LABEL: define i32 @simplify_sle_smax_val
+; CHECK-SAME: (i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT: start:
+; CHECK-NEXT: [[CMP:%.*]] = icmp sle i32 [[A]], [[B]]
+; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK: then:
+; CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[A]], 1
+; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.smax.i32(i32 [[B]], i32 [[ADD]])
+; CHECK-NEXT: ret i32 [[MAX]]
+; CHECK: else:
+; CHECK-NEXT: ret i32 -1
+;
+start:
+ %cmp = icmp sle i32 %a, %b
+ br i1 %cmp, label %then, label %else
+then:
+ %add = add nsw i32 %a, 1
+ %max = call i32 @llvm.smax.i32(i32 %b, i32 %add)
+ ret i32 %max
+else:
+ ret i32 -1
+}
+
+define i32 @simplify_sge_smax_val(i32 %a, i32 %b) {
+; CHECK-LABEL: define i32 @simplify_sge_smax_val
+; CHECK-SAME: (i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT: start:
+; CHECK-NEXT: [[CMP:%.*]] = icmp sge i32 [[A]], [[B]]
+; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK: then:
+; CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[A]], 1
+; CHECK-NEXT: ret i32 [[ADD]]
+; CHECK: else:
+; CHECK-NEXT: ret i32 -1
+;
+start:
+ %cmp = icmp sge i32 %a, %b
+ br i1 %cmp, label %then, label %else
+then:
+ %add = add nsw i32 %a, 1
+ %max = call i32 @llvm.smax.i32(i32 %b, i32 %add)
+ ret i32 %max
+else:
+ ret i32 -1
+}
+
+define i32 @simplify_ult_umax_val(i32 %a, i32 %b) {
+; CHECK-LABEL: define i32 @simplify_ult_umax_val
+; CHECK-SAME: (i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT: start:
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[A]], [[B]]
+; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK: then:
+; CHECK-NEXT: [[ADD:%.*]] = add nuw i32 [[A]], 1
+; CHECK-NEXT: ret i32 [[B]]
+; CHECK: else:
+; CHECK-NEXT: ret i32 -1
+;
+start:
+ %cmp = icmp ult i32 %a, %b
+ br i1 %cmp, label %then, label %else
+then:
+ %add = add nuw i32 %a, 1
+ %max = call i32 @llvm.umax.i32(i32 %b, i32 %add)
+ ret i32 %max
+else:
+ ret i32 -1
+}
+
+define i32 @simplify_slt_smin_val(i32 %a, i32 %b) {
+; CHECK-LABEL: define i32 @simplify_slt_smin_val
+; CHECK-SAME: (i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT: start:
+; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[A]], [[B]]
+; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK: then:
+; CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[A]], 1
+; CHECK-NEXT: ret i32 [[ADD]]
+; CHECK: else:
+; CHECK-NEXT: ret i32 -1
+;
+start:
+ %cmp = icmp slt i32 %a, %b
+ br i1 %cmp, label %then, label %else
+then:
+ %add = add nsw i32 %a, 1
+ %max = call i32 @llvm.smin.i32(i32 %b, i32 %add)
+ ret i32 %max
+else:
+ ret i32 -1
+}
+
+define i32 @simplify_ult_umin_val(i32 %a, i32 %b) {
+; CHECK-LABEL: define i32 @simplify_ult_umin_val
+; CHECK-SAME: (i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT: start:
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[A]], [[B]]
+; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK: then:
+; CHECK-NEXT: [[ADD:%.*]] = add nuw i32 [[A]], 1
+; CHECK-NEXT: ret i32 [[ADD]]
+; CHECK: else:
+; CHECK-NEXT: ret i32 -1
+;
+start:
+ %cmp = icmp ult i32 %a, %b
+ br i1 %cmp, label %then, label %else
+then:
+ %add = add nuw i32 %a, 1
+ %max = call i32 @llvm.umin.i32(i32 %b, i32 %add)
+ ret i32 %max
+else:
+ ret i32 -1
+}
+
+define i32 @simplify_slt_smax_val_fail1(i32 %a, i32 %b) {
+; CHECK-LABEL: define i32 @simplify_slt_smax_val_fail1
+; CHECK-SAME: (i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT: start:
+; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[A]], [[B]]
+; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK: then:
+; CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[A]], 2
+; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.smax.i32(i32 [[B]], i32 [[ADD]])
+; CHECK-NEXT: ret i32 [[MAX]]
+; CHECK: else:
+; CHECK-NEXT: ret i32 -1
+;
+start:
+ %cmp = icmp slt i32 %a, %b
+ br i1 %cmp, label %then, label %else
+then:
+ %add = add nsw i32 %a, 2
+ %max = call i32 @llvm.smax.i32(i32 %b, i32 %add)
+ ret i32 %max
+else:
+ ret i32 -1
+}
+
+define i32 @simplify_ult_smax_val_fail2(i32 %a, i32 %b) {
+; CHECK-LABEL: define i32 @simplify_ult_smax_val_fail2
+; CHECK-SAME: (i32 [[A:%.*]], i32 [[B:%.*]]) {
+; CHECK-NEXT: start:
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[A]], [[B]]
+; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK: then:
+; CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[A]], 1
+; CHECK-NEXT: [[MAX:%.*]] = call i32 @llvm.smax.i32(i32 [[B]], i32 [[ADD]])
+; CHECK-NEXT: ret i32 [[MAX]]
+; CHECK: else:
+; CHECK-NEXT: ret i32 -1
+;
+start:
+ %cmp = icmp ult i32 %a, %b
+ br i1 %cmp, label %then, label %else
+then:
+ %add = add nsw i32 %a, 1
+ %max = call i32 @llvm.smax.i32(i32 %b, i32 %add)
+ ret i32 %max
+else:
+ ret i32 -1
+}
+
declare i32 @llvm.smin.i32(i32, i32)
declare i32 @llvm.smax.i32(i32, i32)
declare i32 @llvm.umin.i32(i32, i32)
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