[llvm-branch-commits] [llvm] PR for llvm/llvm-project#79861 (PR #80832)
via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Tue Feb 20 16:45:35 PST 2024
https://github.com/llvmbot updated https://github.com/llvm/llvm-project/pull/80832
>From 688566b2dfb86c0cd3e896470150282b98b5d8d3 Mon Sep 17 00:00:00 2001
From: Nikita Popov <npopov at redhat.com>
Date: Thu, 1 Feb 2024 12:57:59 +0100
Subject: [PATCH 1/4] [IndVars] Add tests for #79861 (NFC)
(cherry picked from commit c105848fd29d3b46eeb794bb6b10dad04f903b09)
---
.../test/Transforms/IndVarSimplify/pr79861.ll | 104 ++++++++++++++++++
1 file changed, 104 insertions(+)
create mode 100644 llvm/test/Transforms/IndVarSimplify/pr79861.ll
diff --git a/llvm/test/Transforms/IndVarSimplify/pr79861.ll b/llvm/test/Transforms/IndVarSimplify/pr79861.ll
new file mode 100644
index 00000000000000..a8e2aa42a365ce
--- /dev/null
+++ b/llvm/test/Transforms/IndVarSimplify/pr79861.ll
@@ -0,0 +1,104 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt -S -passes=indvars < %s | FileCheck %s
+
+target datalayout = "n64"
+
+declare void @use(i64)
+
+define void @or_disjoint() {
+; CHECK-LABEL: define void @or_disjoint() {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[LOOP:%.*]]
+; CHECK: loop:
+; CHECK-NEXT: [[IV:%.*]] = phi i64 [ 2, [[ENTRY:%.*]] ], [ [[IV_DEC:%.*]], [[LOOP]] ]
+; CHECK-NEXT: [[OR:%.*]] = or disjoint i64 [[IV]], 1
+; CHECK-NEXT: call void @use(i64 [[OR]])
+; CHECK-NEXT: [[IV_DEC]] = add nsw i64 [[IV]], -1
+; CHECK-NEXT: [[EXIT_COND:%.*]] = icmp eq i64 [[IV_DEC]], 0
+; CHECK-NEXT: br i1 [[EXIT_COND]], label [[EXIT:%.*]], label [[LOOP]]
+; CHECK: exit:
+; CHECK-NEXT: ret void
+;
+entry:
+ br label %loop
+
+loop:
+ %iv = phi i64 [ 2, %entry ], [ %iv.dec, %loop ]
+ %or = or disjoint i64 %iv, 1
+ %add = add nsw i64 %iv, 1
+ %sel = select i1 false, i64 %or, i64 %add
+ call void @use(i64 %sel)
+
+ %iv.dec = add nsw i64 %iv, -1
+ %exit.cond = icmp eq i64 %iv.dec, 0
+ br i1 %exit.cond, label %exit, label %loop
+
+exit:
+ ret void
+}
+
+define void @add_nowrap_flags(i64 %n) {
+; CHECK-LABEL: define void @add_nowrap_flags(
+; CHECK-SAME: i64 [[N:%.*]]) {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[LOOP:%.*]]
+; CHECK: loop:
+; CHECK-NEXT: [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_INC:%.*]], [[LOOP]] ]
+; CHECK-NEXT: [[ADD1:%.*]] = add nuw nsw i64 [[IV]], 123
+; CHECK-NEXT: call void @use(i64 [[ADD1]])
+; CHECK-NEXT: [[IV_INC]] = add i64 [[IV]], 1
+; CHECK-NEXT: [[EXIT_COND:%.*]] = icmp eq i64 [[IV_INC]], [[N]]
+; CHECK-NEXT: br i1 [[EXIT_COND]], label [[EXIT:%.*]], label [[LOOP]]
+; CHECK: exit:
+; CHECK-NEXT: ret void
+;
+entry:
+ br label %loop
+
+loop:
+ %iv = phi i64 [ 0, %entry ], [ %iv.inc, %loop ]
+ %add1 = add nuw nsw i64 %iv, 123
+ %add2 = add i64 %iv, 123
+ %sel = select i1 false, i64 %add1, i64 %add2
+ call void @use(i64 %sel)
+
+ %iv.inc = add i64 %iv, 1
+ %exit.cond = icmp eq i64 %iv.inc, %n
+ br i1 %exit.cond, label %exit, label %loop
+
+exit:
+ ret void
+}
+
+
+define void @expander_or_disjoint(i64 %n) {
+; CHECK-LABEL: define void @expander_or_disjoint(
+; CHECK-SAME: i64 [[N:%.*]]) {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[OR:%.*]] = or i64 [[N]], 1
+; CHECK-NEXT: br label [[LOOP:%.*]]
+; CHECK: loop:
+; CHECK-NEXT: [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_INC:%.*]], [[LOOP]] ]
+; CHECK-NEXT: [[IV_INC]] = add i64 [[IV]], 1
+; CHECK-NEXT: [[ADD:%.*]] = add i64 [[IV]], [[OR]]
+; CHECK-NEXT: call void @use(i64 [[ADD]])
+; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i64 [[IV_INC]], [[OR]]
+; CHECK-NEXT: br i1 [[EXITCOND]], label [[LOOP]], label [[EXIT:%.*]]
+; CHECK: exit:
+; CHECK-NEXT: ret void
+;
+entry:
+ %or = or disjoint i64 %n, 1
+ br label %loop
+
+loop:
+ %iv = phi i64 [ 0, %entry ], [ %iv.inc, %loop ]
+ %iv.inc = add i64 %iv, 1
+ %add = add i64 %iv, %or
+ call void @use(i64 %add)
+ %cmp = icmp ult i64 %iv, %n
+ br i1 %cmp, label %loop, label %exit
+
+exit:
+ ret void
+}
>From 4223b2264ce5e6d1855b9e7b32fe61152a681046 Mon Sep 17 00:00:00 2001
From: Nikita Popov <npopov at redhat.com>
Date: Fri, 2 Feb 2024 10:52:05 +0100
Subject: [PATCH 2/4] [SCEVExpander] Do not reuse disjoint or (#80281)
SCEV treats "or disjoint" the same as "add nsw nuw". However, when
expanding, we cannot generally replace an add SCEV node with an "or
disjoint" instruction. Just dropping the poison flag is insufficient in
this case, we would have to actually convert the or into an add.
This is a partial fix for #79861.
(cherry picked from commit 5b8e1a6ebf11b6e93bcc96a0d009febe4bb3d7bc)
---
llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp | 7 +++++++
llvm/test/Transforms/IndVarSimplify/pr79861.ll | 5 +++--
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
index a1d7f0f9ba0f74..e6f93e72c98a77 100644
--- a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
+++ b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
@@ -1401,6 +1401,13 @@ canReuseInstruction(ScalarEvolution &SE, const SCEV *S, Instruction *I,
if (!I)
return false;
+ // Disjoint or instructions are interpreted as adds by SCEV. However, we
+ // can't replace an arbitrary add with disjoint or, even if we drop the
+ // flag. We would need to convert the or into an add.
+ if (auto *PDI = dyn_cast<PossiblyDisjointInst>(I))
+ if (PDI->isDisjoint())
+ return false;
+
// FIXME: Ignore vscale, even though it technically could be poison. Do this
// because SCEV currently assumes it can't be poison. Remove this special
// case once we proper model when vscale can be poison.
diff --git a/llvm/test/Transforms/IndVarSimplify/pr79861.ll b/llvm/test/Transforms/IndVarSimplify/pr79861.ll
index a8e2aa42a365ce..7e267d04c94cc8 100644
--- a/llvm/test/Transforms/IndVarSimplify/pr79861.ll
+++ b/llvm/test/Transforms/IndVarSimplify/pr79861.ll
@@ -75,14 +75,15 @@ define void @expander_or_disjoint(i64 %n) {
; CHECK-LABEL: define void @expander_or_disjoint(
; CHECK-SAME: i64 [[N:%.*]]) {
; CHECK-NEXT: entry:
-; CHECK-NEXT: [[OR:%.*]] = or i64 [[N]], 1
+; CHECK-NEXT: [[OR:%.*]] = or disjoint i64 [[N]], 1
+; CHECK-NEXT: [[TMP0:%.*]] = add i64 [[N]], 1
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_INC:%.*]], [[LOOP]] ]
; CHECK-NEXT: [[IV_INC]] = add i64 [[IV]], 1
; CHECK-NEXT: [[ADD:%.*]] = add i64 [[IV]], [[OR]]
; CHECK-NEXT: call void @use(i64 [[ADD]])
-; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i64 [[IV_INC]], [[OR]]
+; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i64 [[IV_INC]], [[TMP0]]
; CHECK-NEXT: br i1 [[EXITCOND]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK: exit:
; CHECK-NEXT: ret void
>From dc0ed54ac582357c8e097b2610791b7f802bb0ad Mon Sep 17 00:00:00 2001
From: Nikita Popov <npopov at redhat.com>
Date: Fri, 2 Feb 2024 16:02:46 +0100
Subject: [PATCH 3/4] [SCEV] Move canReuseInstruction() helper into SCEV (NFC)
To allow reusing it in IndVars.
(cherry picked from commit 43dd1e84df1ecdad872e1004af47b489e08fc228)
---
llvm/include/llvm/Analysis/ScalarEvolution.h | 7 ++
llvm/lib/Analysis/ScalarEvolution.cpp | 62 ++++++++++++++++++
.../Utils/ScalarEvolutionExpander.cpp | 64 +------------------
3 files changed, 70 insertions(+), 63 deletions(-)
diff --git a/llvm/include/llvm/Analysis/ScalarEvolution.h b/llvm/include/llvm/Analysis/ScalarEvolution.h
index af3ad822e0b0de..0880f9c65aa45d 100644
--- a/llvm/include/llvm/Analysis/ScalarEvolution.h
+++ b/llvm/include/llvm/Analysis/ScalarEvolution.h
@@ -1314,6 +1314,13 @@ class ScalarEvolution {
void getPoisonGeneratingValues(SmallPtrSetImpl<const Value *> &Result,
const SCEV *S);
+ /// Check whether it is poison-safe to represent the expression S using the
+ /// instruction I. If such a replacement is performed, the poison flags of
+ /// instructions in DropPoisonGeneratingInsts must be dropped.
+ bool canReuseInstruction(
+ const SCEV *S, Instruction *I,
+ SmallVectorImpl<Instruction *> &DropPoisonGeneratingInsts);
+
class FoldID {
const SCEV *Op = nullptr;
const Type *Ty = nullptr;
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 2acb45837c480a..4b2db80bc1ec30 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -4184,6 +4184,68 @@ void ScalarEvolution::getPoisonGeneratingValues(
Result.insert(SU->getValue());
}
+bool ScalarEvolution::canReuseInstruction(
+ const SCEV *S, Instruction *I,
+ SmallVectorImpl<Instruction *> &DropPoisonGeneratingInsts) {
+ // If the instruction cannot be poison, it's always safe to reuse.
+ if (programUndefinedIfPoison(I))
+ return true;
+
+ // Otherwise, it is possible that I is more poisonous that S. Collect the
+ // poison-contributors of S, and then check whether I has any additional
+ // poison-contributors. Poison that is contributed through poison-generating
+ // flags is handled by dropping those flags instead.
+ SmallPtrSet<const Value *, 8> PoisonVals;
+ getPoisonGeneratingValues(PoisonVals, S);
+
+ SmallVector<Value *> Worklist;
+ SmallPtrSet<Value *, 8> Visited;
+ Worklist.push_back(I);
+ while (!Worklist.empty()) {
+ Value *V = Worklist.pop_back_val();
+ if (!Visited.insert(V).second)
+ continue;
+
+ // Avoid walking large instruction graphs.
+ if (Visited.size() > 16)
+ return false;
+
+ // Either the value can't be poison, or the S would also be poison if it
+ // is.
+ if (PoisonVals.contains(V) || isGuaranteedNotToBePoison(V))
+ continue;
+
+ auto *I = dyn_cast<Instruction>(V);
+ if (!I)
+ return false;
+
+ // Disjoint or instructions are interpreted as adds by SCEV. However, we
+ // can't replace an arbitrary add with disjoint or, even if we drop the
+ // flag. We would need to convert the or into an add.
+ if (auto *PDI = dyn_cast<PossiblyDisjointInst>(I))
+ if (PDI->isDisjoint())
+ return false;
+
+ // FIXME: Ignore vscale, even though it technically could be poison. Do this
+ // because SCEV currently assumes it can't be poison. Remove this special
+ // case once we proper model when vscale can be poison.
+ if (auto *II = dyn_cast<IntrinsicInst>(I);
+ II && II->getIntrinsicID() == Intrinsic::vscale)
+ continue;
+
+ if (canCreatePoison(cast<Operator>(I), /*ConsiderFlagsAndMetadata*/ false))
+ return false;
+
+ // If the instruction can't create poison, we can recurse to its operands.
+ if (I->hasPoisonGeneratingFlagsOrMetadata())
+ DropPoisonGeneratingInsts.push_back(I);
+
+ for (Value *Op : I->operands())
+ Worklist.push_back(Op);
+ }
+ return true;
+}
+
const SCEV *
ScalarEvolution::getSequentialMinMaxExpr(SCEVTypes Kind,
SmallVectorImpl<const SCEV *> &Ops) {
diff --git a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
index e6f93e72c98a77..a3951fdf8a1589 100644
--- a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
+++ b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
@@ -1366,68 +1366,6 @@ Value *SCEVExpander::expandCodeFor(const SCEV *SH, Type *Ty) {
return V;
}
-static bool
-canReuseInstruction(ScalarEvolution &SE, const SCEV *S, Instruction *I,
- SmallVectorImpl<Instruction *> &DropPoisonGeneratingInsts) {
- // If the instruction cannot be poison, it's always safe to reuse.
- if (programUndefinedIfPoison(I))
- return true;
-
- // Otherwise, it is possible that I is more poisonous that S. Collect the
- // poison-contributors of S, and then check whether I has any additional
- // poison-contributors. Poison that is contributed through poison-generating
- // flags is handled by dropping those flags instead.
- SmallPtrSet<const Value *, 8> PoisonVals;
- SE.getPoisonGeneratingValues(PoisonVals, S);
-
- SmallVector<Value *> Worklist;
- SmallPtrSet<Value *, 8> Visited;
- Worklist.push_back(I);
- while (!Worklist.empty()) {
- Value *V = Worklist.pop_back_val();
- if (!Visited.insert(V).second)
- continue;
-
- // Avoid walking large instruction graphs.
- if (Visited.size() > 16)
- return false;
-
- // Either the value can't be poison, or the S would also be poison if it
- // is.
- if (PoisonVals.contains(V) || isGuaranteedNotToBePoison(V))
- continue;
-
- auto *I = dyn_cast<Instruction>(V);
- if (!I)
- return false;
-
- // Disjoint or instructions are interpreted as adds by SCEV. However, we
- // can't replace an arbitrary add with disjoint or, even if we drop the
- // flag. We would need to convert the or into an add.
- if (auto *PDI = dyn_cast<PossiblyDisjointInst>(I))
- if (PDI->isDisjoint())
- return false;
-
- // FIXME: Ignore vscale, even though it technically could be poison. Do this
- // because SCEV currently assumes it can't be poison. Remove this special
- // case once we proper model when vscale can be poison.
- if (auto *II = dyn_cast<IntrinsicInst>(I);
- II && II->getIntrinsicID() == Intrinsic::vscale)
- continue;
-
- if (canCreatePoison(cast<Operator>(I), /*ConsiderFlagsAndMetadata*/ false))
- return false;
-
- // If the instruction can't create poison, we can recurse to its operands.
- if (I->hasPoisonGeneratingFlagsOrMetadata())
- DropPoisonGeneratingInsts.push_back(I);
-
- for (Value *Op : I->operands())
- Worklist.push_back(Op);
- }
- return true;
-}
-
Value *SCEVExpander::FindValueInExprValueMap(
const SCEV *S, const Instruction *InsertPt,
SmallVectorImpl<Instruction *> &DropPoisonGeneratingInsts) {
@@ -1455,7 +1393,7 @@ Value *SCEVExpander::FindValueInExprValueMap(
continue;
// Make sure reusing the instruction is poison-safe.
- if (canReuseInstruction(SE, S, EntInst, DropPoisonGeneratingInsts))
+ if (SE.canReuseInstruction(S, EntInst, DropPoisonGeneratingInsts))
return V;
DropPoisonGeneratingInsts.clear();
}
>From 94dcc1d6ae0912910c1a001da54ca64171d36374 Mon Sep 17 00:00:00 2001
From: Nikita Popov <npopov at redhat.com>
Date: Mon, 5 Feb 2024 10:11:39 +0100
Subject: [PATCH 4/4] [IndVarSimplify] Fix poison-safety when reusing
instructions (#80458)
IndVars may replace an instruction with one of its operands, if they
have the same SCEV expression. However, such a replacement may be more
poisonous.
First, check whether the operand being poison implies that the
instruction is also poison, in which case the replacement is always
safe. If this fails, check whether SCEV can determine that reusing the
instruction is safe, using the same check as SCEVExpander.
Fixes https://github.com/llvm/llvm-project/issues/79861.
(cherry picked from commit 7d2b6f0b355bc98bbe3aa5bae83316a708da33ee)
---
llvm/lib/Transforms/Utils/SimplifyIndVar.cpp | 18 ++++++++++++++++--
llvm/test/Transforms/IndVarSimplify/pr55925.ll | 4 ++--
llvm/test/Transforms/IndVarSimplify/pr79861.ll | 6 ++++--
3 files changed, 22 insertions(+), 6 deletions(-)
diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
index 0ed3324a27b6c9..1b142f14d81139 100644
--- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -16,6 +16,7 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instructions.h"
@@ -713,8 +714,11 @@ bool SimplifyIndvar::replaceFloatIVWithIntegerIV(Instruction *UseInst) {
bool SimplifyIndvar::eliminateIdentitySCEV(Instruction *UseInst,
Instruction *IVOperand) {
if (!SE->isSCEVable(UseInst->getType()) ||
- (UseInst->getType() != IVOperand->getType()) ||
- (SE->getSCEV(UseInst) != SE->getSCEV(IVOperand)))
+ UseInst->getType() != IVOperand->getType())
+ return false;
+
+ const SCEV *UseSCEV = SE->getSCEV(UseInst);
+ if (UseSCEV != SE->getSCEV(IVOperand))
return false;
// getSCEV(X) == getSCEV(Y) does not guarantee that X and Y are related in the
@@ -742,6 +746,16 @@ bool SimplifyIndvar::eliminateIdentitySCEV(Instruction *UseInst,
if (!LI->replacementPreservesLCSSAForm(UseInst, IVOperand))
return false;
+ // Make sure the operand is not more poisonous than the instruction.
+ if (!impliesPoison(IVOperand, UseInst)) {
+ SmallVector<Instruction *> DropPoisonGeneratingInsts;
+ if (!SE->canReuseInstruction(UseSCEV, IVOperand, DropPoisonGeneratingInsts))
+ return false;
+
+ for (Instruction *I : DropPoisonGeneratingInsts)
+ I->dropPoisonGeneratingFlagsAndMetadata();
+ }
+
LLVM_DEBUG(dbgs() << "INDVARS: Eliminated identity: " << *UseInst << '\n');
SE->forgetValue(UseInst);
diff --git a/llvm/test/Transforms/IndVarSimplify/pr55925.ll b/llvm/test/Transforms/IndVarSimplify/pr55925.ll
index 420fc209949d4f..312a8295ccdc9f 100644
--- a/llvm/test/Transforms/IndVarSimplify/pr55925.ll
+++ b/llvm/test/Transforms/IndVarSimplify/pr55925.ll
@@ -18,9 +18,9 @@ define void @test(ptr %p) personality ptr undef {
; CHECK-NEXT: [[RES:%.*]] = invoke i32 @foo(i32 returned [[TMP0]])
; CHECK-NEXT: to label [[LOOP_LATCH]] unwind label [[EXIT:%.*]]
; CHECK: loop.latch:
-; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add i64 [[INDVARS_IV]], 1
; CHECK-NEXT: [[TMP1:%.*]] = trunc i64 [[INDVARS_IV]] to i32
; CHECK-NEXT: [[TMP2:%.*]] = call i32 @foo(i32 [[TMP1]])
+; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add i64 [[INDVARS_IV]], 1
; CHECK-NEXT: br label [[LOOP]]
; CHECK: exit:
; CHECK-NEXT: [[LP:%.*]] = landingpad { ptr, i32 }
@@ -64,8 +64,8 @@ define void @test_critedge(i1 %c, ptr %p) personality ptr undef {
; CHECK-NEXT: br label [[LOOP_LATCH]]
; CHECK: loop.latch:
; CHECK-NEXT: [[PHI:%.*]] = phi i32 [ [[TMP1]], [[LOOP_INVOKE]] ], [ 0, [[LOOP_OTHER]] ]
-; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add i64 [[INDVARS_IV]], 1
; CHECK-NEXT: [[TMP2:%.*]] = call i32 @foo(i32 [[PHI]])
+; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add i64 [[INDVARS_IV]], 1
; CHECK-NEXT: br label [[LOOP]]
; CHECK: exit:
; CHECK-NEXT: [[LP:%.*]] = landingpad { ptr, i32 }
diff --git a/llvm/test/Transforms/IndVarSimplify/pr79861.ll b/llvm/test/Transforms/IndVarSimplify/pr79861.ll
index 7e267d04c94cc8..66250944961397 100644
--- a/llvm/test/Transforms/IndVarSimplify/pr79861.ll
+++ b/llvm/test/Transforms/IndVarSimplify/pr79861.ll
@@ -12,7 +12,9 @@ define void @or_disjoint() {
; CHECK: loop:
; CHECK-NEXT: [[IV:%.*]] = phi i64 [ 2, [[ENTRY:%.*]] ], [ [[IV_DEC:%.*]], [[LOOP]] ]
; CHECK-NEXT: [[OR:%.*]] = or disjoint i64 [[IV]], 1
-; CHECK-NEXT: call void @use(i64 [[OR]])
+; CHECK-NEXT: [[ADD:%.*]] = add nuw nsw i64 [[IV]], 1
+; CHECK-NEXT: [[SEL:%.*]] = select i1 false, i64 [[OR]], i64 [[ADD]]
+; CHECK-NEXT: call void @use(i64 [[SEL]])
; CHECK-NEXT: [[IV_DEC]] = add nsw i64 [[IV]], -1
; CHECK-NEXT: [[EXIT_COND:%.*]] = icmp eq i64 [[IV_DEC]], 0
; CHECK-NEXT: br i1 [[EXIT_COND]], label [[EXIT:%.*]], label [[LOOP]]
@@ -44,7 +46,7 @@ define void @add_nowrap_flags(i64 %n) {
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_INC:%.*]], [[LOOP]] ]
-; CHECK-NEXT: [[ADD1:%.*]] = add nuw nsw i64 [[IV]], 123
+; CHECK-NEXT: [[ADD1:%.*]] = add i64 [[IV]], 123
; CHECK-NEXT: call void @use(i64 [[ADD1]])
; CHECK-NEXT: [[IV_INC]] = add i64 [[IV]], 1
; CHECK-NEXT: [[EXIT_COND:%.*]] = icmp eq i64 [[IV_INC]], [[N]]
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