[llvm] [PredicateInfo] Support existing `PredicateType` by adding `PredicatePHI` when needing introduction of phi nodes (PR #151132)
Rajveer Singh Bharadwaj via llvm-commits
llvm-commits at lists.llvm.org
Fri Aug 15 03:37:09 PDT 2025
https://github.com/Rajveer100 updated https://github.com/llvm/llvm-project/pull/151132
>From f1692ac2353c53de00c1bcdcd6872b97675ef8e6 Mon Sep 17 00:00:00 2001
From: Rajveer <rajveer.developer at icloud.com>
Date: Tue, 29 Jul 2025 17:21:36 +0530
Subject: [PATCH] [PredicateInfo] Support existing `PredicateType` by adding
`PredicatePHI` when needing introduction of phi nodes
Resolves #150606
Currently `ssa.copy` is used mostly for straight line code, i.e, without
joins or uses of phi nodes. With this, passes would be able to pick up the
relevant info and further optimize the IR.
---
.../llvm/Transforms/Utils/PredicateInfo.h | 15 +-
llvm/lib/Transforms/Utils/PredicateInfo.cpp | 153 ++++++++++++++++++
.../LoopVersioningLICM/loopversioningLICM1.ll | 4 +-
.../Transforms/NewGVN/phi-predicate-opt.ll | 39 +++++
llvm/test/Transforms/NewGVN/pr33116.ll | 4 +-
llvm/test/Transforms/NewGVN/pr33204.ll | 4 +-
llvm/test/Transforms/NewGVN/pr33720.ll | 6 +-
.../Util/PredicateInfo/phi-predicate.ll | 43 +++++
8 files changed, 258 insertions(+), 10 deletions(-)
create mode 100644 llvm/test/Transforms/NewGVN/phi-predicate-opt.ll
create mode 100644 llvm/test/Transforms/Util/PredicateInfo/phi-predicate.ll
diff --git a/llvm/include/llvm/Transforms/Utils/PredicateInfo.h b/llvm/include/llvm/Transforms/Utils/PredicateInfo.h
index 3df3495f84470..e3b394127b75a 100644
--- a/llvm/include/llvm/Transforms/Utils/PredicateInfo.h
+++ b/llvm/include/llvm/Transforms/Utils/PredicateInfo.h
@@ -67,7 +67,7 @@ class Value;
class IntrinsicInst;
class raw_ostream;
-enum PredicateType { PT_Branch, PT_Assume, PT_Switch };
+enum PredicateType { PT_Branch, PT_Assume, PT_Switch, PT_PHI };
/// Constraint for a predicate of the form "cmp Pred Op, OtherOp", where Op
/// is the value the constraint applies to (the bitcast result).
@@ -171,6 +171,19 @@ class PredicateSwitch : public PredicateWithEdge {
}
};
+class PredicatePHI : public PredicateBase {
+public:
+ BasicBlock *PHIBlock;
+ SmallVector<std::pair<BasicBlock *, PredicateBase *>, 4> IncomingPredicates;
+
+ PredicatePHI(Value *Op, BasicBlock *PHIBB)
+ : PredicateBase(PT_PHI, Op, nullptr), PHIBlock(PHIBB) {}
+ PredicatePHI() = delete;
+ static bool classof(const PredicateBase *PB) { return PB->Type == PT_PHI; }
+
+ LLVM_ABI std::optional<PredicateConstraint> getConstraint() const;
+};
+
/// Encapsulates PredicateInfo, including all data associated with memory
/// accesses.
class PredicateInfo {
diff --git a/llvm/lib/Transforms/Utils/PredicateInfo.cpp b/llvm/lib/Transforms/Utils/PredicateInfo.cpp
index 13c7ad2927d1c..20adf5656d3ef 100644
--- a/llvm/lib/Transforms/Utils/PredicateInfo.cpp
+++ b/llvm/lib/Transforms/Utils/PredicateInfo.cpp
@@ -15,7 +15,9 @@
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/IteratedDominanceFrontier.h"
#include "llvm/IR/AssemblyAnnotationWriter.h"
+#include "llvm/IR/CFG.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstIterator.h"
@@ -213,6 +215,8 @@ class PredicateInfoBuilder {
// whether it returned a valid result.
DenseMap<Value *, unsigned int> ValueInfoNums;
+ DenseMap<BasicBlock *, SmallVector<Value *, 4>> PHICandidates;
+
BumpPtrAllocator &Allocator;
ValueInfo &getOrCreateValueInfo(Value *);
@@ -224,6 +228,13 @@ class PredicateInfoBuilder {
SmallVectorImpl<Value *> &OpsToRename);
void processSwitch(SwitchInst *, BasicBlock *,
SmallVectorImpl<Value *> &OpsToRename);
+ void identifyPHICandidates(SmallVectorImpl<Value *> &OpsToRename);
+ void needsPHIInsertion(Value *Op,
+ const SmallPtrSetImpl<BasicBlock *> &DefiningBlocks,
+ SmallPtrSetImpl<BasicBlock *> &PHIBlocks);
+ void insertPredicatePHIs(Value *Op, BasicBlock *PHIBlock,
+ SmallVectorImpl<Value *> &OpsToRename);
+ void processPredicatePHIs(SmallVectorImpl<Value *> &OpsToRename);
void renameUses(SmallVectorImpl<Value *> &OpsToRename);
void addInfoFor(SmallVectorImpl<Value *> &OpsToRename, Value *Op,
PredicateBase *PB);
@@ -461,6 +472,103 @@ void PredicateInfoBuilder::processSwitch(
}
}
+void PredicateInfoBuilder::identifyPHICandidates(
+ SmallVectorImpl<Value *> &OpsToRename) {
+ for (Value *Op : OpsToRename) {
+ const auto &ValueInfo = getValueInfo(Op);
+ SmallPtrSet<BasicBlock *, 4> DefiningBlocks;
+ for (const auto *PInfo : ValueInfo.Infos) {
+ if (auto *PBranch = dyn_cast<PredicateBranch>(PInfo)) {
+ DefiningBlocks.insert(PBranch->From);
+ } else if (auto *PSwitch = dyn_cast<PredicateSwitch>(PInfo)) {
+ DefiningBlocks.insert(PSwitch->From);
+ }
+ }
+
+ if (DefiningBlocks.size() > 1) {
+ SmallPtrSet<BasicBlock *, 8> PHIBlocks;
+ needsPHIInsertion(Op, DefiningBlocks, PHIBlocks);
+ for (BasicBlock *PHIBlock : PHIBlocks) {
+ PHICandidates[PHIBlock].push_back(Op);
+ }
+ }
+ }
+}
+
+void PredicateInfoBuilder::needsPHIInsertion(
+ Value *Op, const SmallPtrSetImpl<BasicBlock *> &DefiningBlocks,
+ SmallPtrSetImpl<BasicBlock *> &PHIBlocks) {
+ IDFCalculator<false> IDF(DT);
+ IDF.setDefiningBlocks(DefiningBlocks);
+
+ SmallPtrSet<BasicBlock *, 8> LiveInBlocks;
+ for (auto CurUser = Op->users().begin(); CurUser != Op->users().end();
+ ++CurUser) {
+ if (auto *I = dyn_cast<Instruction>(*CurUser)) {
+ LiveInBlocks.insert(I->getParent());
+ }
+ }
+ IDF.setLiveInBlocks(LiveInBlocks);
+
+ SmallVector<BasicBlock *, 4> IDFBlocks;
+ IDF.calculate(IDFBlocks);
+
+ for (const auto &IDFBlock : IDFBlocks) {
+ PHIBlocks.insert(std::move(IDFBlock));
+ }
+}
+
+void PredicateInfoBuilder::insertPredicatePHIs(
+ Value *Op, BasicBlock *PHIBlock, SmallVectorImpl<Value *> &OpsToRename) {
+ IRBuilder<> Builder(&PHIBlock->front());
+
+ PHINode *PHI = Builder.CreatePHI(Op->getType(), pred_size(PHIBlock),
+ Op->getName() + ".predicate.phi");
+ PredicatePHI *PPHI = new (Allocator) PredicatePHI(Op, PHIBlock);
+ PPHI->RenamedOp = PHI;
+
+ const auto &ValueInfo = getValueInfo(Op);
+
+ for (BasicBlock *Pred : predecessors(PHIBlock)) {
+ Value *IncomingValue = nullptr;
+ for (const auto *PInfo : ValueInfo.Infos) {
+ if (auto *PBranch = dyn_cast<PredicateBranch>(PInfo)) {
+ if (PBranch->From == Pred && PBranch->To == PHIBlock) {
+ PPHI->IncomingPredicates.push_back(
+ {Pred, const_cast<PredicateBase *>(PInfo)});
+ IncomingValue = PBranch->OriginalOp;
+ }
+ } else if (auto *PSwitch = dyn_cast<PredicateSwitch>(PInfo)) {
+ if (PSwitch->From == Pred && PSwitch->To == PHIBlock) {
+ PPHI->IncomingPredicates.push_back(
+ {Pred, const_cast<PredicateBase *>(PInfo)});
+ IncomingValue = PSwitch->OriginalOp;
+ }
+ }
+ }
+ if (IncomingValue) {
+ PHI->addIncoming(IncomingValue, Pred);
+ } else {
+ PHI->eraseFromParent();
+ PPHI->RenamedOp = nullptr;
+ PPHI->IncomingPredicates.clear();
+ return;
+ }
+ }
+
+ addInfoFor(OpsToRename, Op, PPHI);
+}
+
+void PredicateInfoBuilder::processPredicatePHIs(
+ SmallVectorImpl<Value *> &OpsToRename) {
+ for (const auto &PHICandidate : PHICandidates) {
+ BasicBlock *PHIBlock = PHICandidate.first;
+ for (Value *Op : PHICandidate.second) {
+ insertPredicatePHIs(Op, PHIBlock, OpsToRename);
+ }
+ }
+}
+
// Build predicate info for our function
void PredicateInfoBuilder::buildPredicateInfo() {
DT.updateDFSNumbers();
@@ -487,6 +595,10 @@ void PredicateInfoBuilder::buildPredicateInfo() {
if (DT.isReachableFromEntry(II->getParent()))
processAssume(II, II->getParent(), OpsToRename);
}
+
+ identifyPHICandidates(OpsToRename);
+ processPredicatePHIs(OpsToRename);
+
// Now rename all our operations.
renameUses(OpsToRename);
}
@@ -530,6 +642,13 @@ Value *PredicateInfoBuilder::materializeStack(unsigned int &Counter,
Op->getName() + "." + Twine(Counter++));
PI.PredicateMap.insert({PIC, ValInfo});
Result.Def = PIC;
+ } else if (isa<PredicatePHI>(ValInfo)) {
+ auto *PPHI = dyn_cast<PredicatePHI>(ValInfo);
+ IRBuilder<> B(&*PPHI->PHIBlock->getFirstInsertionPt());
+ BitCastInst *PIC =
+ CreateSSACopy(&*PPHI->PHIBlock->getFirstInsertionPt(), Op);
+ PI.PredicateMap.insert({PIC, ValInfo});
+ Result.Def = PIC;
} else {
auto *PAssume = dyn_cast<PredicateAssume>(ValInfo);
assert(PAssume &&
@@ -617,6 +736,15 @@ void PredicateInfoBuilder::renameUses(SmallVectorImpl<Value *> &OpsToRename) {
OrderedUses.push_back(VD);
}
}
+ } else if (const auto *PPHI = dyn_cast<PredicatePHI>(PossibleCopy)) {
+ VD.LocalNum = LN_First;
+ auto *DomNode = DT.getNode(PPHI->PHIBlock);
+ if (DomNode) {
+ VD.DFSIn = DomNode->getDFSNumIn();
+ VD.DFSOut = DomNode->getDFSNumOut();
+ VD.PInfo = PossibleCopy;
+ OrderedUses.push_back(VD);
+ }
}
}
@@ -755,10 +883,31 @@ std::optional<PredicateConstraint> PredicateBase::getConstraint() const {
}
return {{CmpInst::ICMP_EQ, cast<PredicateSwitch>(this)->CaseValue}};
+ case PT_PHI:
+ return cast<PredicatePHI>(this)->getConstraint();
}
llvm_unreachable("Unknown predicate type");
}
+std::optional<PredicateConstraint> PredicatePHI::getConstraint() const {
+ if (IncomingPredicates.empty())
+ return std::nullopt;
+
+ auto FirstConstraint = IncomingPredicates[0].second->getConstraint();
+ if (!FirstConstraint)
+ return std::nullopt;
+
+ for (size_t I = 1; I < IncomingPredicates.size(); ++I) {
+ auto Constraint = IncomingPredicates[I].second->getConstraint();
+ if (!Constraint || Constraint->Predicate != FirstConstraint->Predicate ||
+ Constraint->OtherOp != FirstConstraint->OtherOp) {
+ return std::nullopt;
+ }
+ }
+
+ return FirstConstraint;
+}
+
void PredicateInfo::verifyPredicateInfo() const {}
// Replace bitcasts created by PredicateInfo with their operand.
@@ -821,6 +970,10 @@ class PredicateInfoAnnotatedWriter : public AssemblyAnnotationWriter {
} else if (const auto *PA = dyn_cast<PredicateAssume>(PI)) {
OS << "; assume predicate info {"
<< " Comparison:" << *PA->Condition;
+ } else if (const auto *PP = dyn_cast<PredicatePHI>(PI)) {
+ OS << "; phi predicate info { PHIBlock: ";
+ PP->PHIBlock->printAsOperand(OS);
+ OS << " IncomingEdges: " << PP->IncomingPredicates.size();
}
OS << ", RenamedOp: ";
PI->RenamedOp->printAsOperand(OS, false);
diff --git a/llvm/test/Transforms/LoopVersioningLICM/loopversioningLICM1.ll b/llvm/test/Transforms/LoopVersioningLICM/loopversioningLICM1.ll
index b4f8abbf83a53..3b194a88c7ea0 100644
--- a/llvm/test/Transforms/LoopVersioningLICM/loopversioningLICM1.ll
+++ b/llvm/test/Transforms/LoopVersioningLICM/loopversioningLICM1.ll
@@ -68,10 +68,10 @@ define i32 @foo(ptr nocapture %var1, ptr nocapture readnone %var2, ptr nocapture
; CHECK-NEXT: [[ADD8]] = add nsw i32 [[ADD86]], [[ADD]]
; CHECK-NEXT: [[INC]] = add nuw i32 [[J_113]], 1
; CHECK-NEXT: [[CMP2:%.*]] = icmp ult i32 [[INC]], [[ITR]]
-; CHECK-NEXT: br i1 [[CMP2]], label [[FOR_BODY3]], label [[FOR_INC11_LOOPEXIT_LOOPEXIT5:%.*]], !llvm.loop [[LOOP7:![0-9]+]]
+; CHECK-NEXT: br i1 [[CMP2]], label [[FOR_BODY3]], label [[FOR_INC11_LOOPEXIT_LOOPEXIT7:%.*]], !llvm.loop [[LOOP7:![0-9]+]]
; CHECK: for.inc11.loopexit.loopexit:
; CHECK-NEXT: br label [[FOR_INC11_LOOPEXIT:%.*]]
-; CHECK: for.inc11.loopexit.loopexit5:
+; CHECK: for.inc11.loopexit.loopexit7:
; CHECK-NEXT: [[ADD8_LCSSA:%.*]] = phi i32 [ [[ADD8]], [[FOR_BODY3]] ]
; CHECK-NEXT: store i32 [[ADD8_LCSSA]], ptr [[ARRAYIDX7]], align 4, !alias.scope [[META2]]
; CHECK-NEXT: br label [[FOR_INC11_LOOPEXIT]]
diff --git a/llvm/test/Transforms/NewGVN/phi-predicate-opt.ll b/llvm/test/Transforms/NewGVN/phi-predicate-opt.ll
new file mode 100644
index 0000000000000..1164cce689f02
--- /dev/null
+++ b/llvm/test/Transforms/NewGVN/phi-predicate-opt.ll
@@ -0,0 +1,39 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes=newgvn -S | FileCheck %s
+
+ at p = local_unnamed_addr global i32 0
+
+define noundef i32 @h5diff(i32 %0, i1 %1) local_unnamed_addr #0 {
+; CHECK-LABEL: @h5diff(
+; CHECK-NEXT: [[COND:%.*]] = icmp eq i32 [[TMP0:%.*]], 0
+; CHECK-NEXT: br i1 [[TMP1:%.*]], label [[TMP3:%.*]], label [[TMP4:%.*]]
+; CHECK: 3:
+; CHECK-NEXT: store i32 1, ptr @p, align 4
+; CHECK-NEXT: br i1 [[COND]], label [[TMP5:%.*]], label [[COMMON_RET:%.*]]
+; CHECK: common.ret:
+; CHECK-NEXT: ret i32 0
+; CHECK: 4:
+; CHECK-NEXT: store i32 2, ptr @p, align 4
+; CHECK-NEXT: br i1 [[COND]], label [[TMP5]], label [[COMMON_RET]]
+; CHECK: 5:
+; CHECK-NEXT: store i32 0, ptr @p, align 4
+; CHECK-NEXT: br label [[COMMON_RET]]
+;
+ %cond = icmp eq i32 %0, 0
+ br i1 %1, label %3, label %4
+
+3:
+ store i32 1, ptr @p, align 4
+ br i1 %cond, label %5, label %common.ret
+
+common.ret:
+ ret i32 0
+
+4:
+ store i32 2, ptr @p, align 4
+ br i1 %cond, label %5, label %common.ret
+
+5:
+ store i32 %0, ptr @p, align 4
+ br label %common.ret
+}
diff --git a/llvm/test/Transforms/NewGVN/pr33116.ll b/llvm/test/Transforms/NewGVN/pr33116.ll
index a0dc3b2382f91..3d272d3efaaf3 100644
--- a/llvm/test/Transforms/NewGVN/pr33116.ll
+++ b/llvm/test/Transforms/NewGVN/pr33116.ll
@@ -9,9 +9,9 @@ define void @b(i1 %arg) {
; CHECK: while.d:
; CHECK-NEXT: br label [[F:%.*]]
; CHECK: f:
-; CHECK-NEXT: br i1 %arg, label [[IF_E:%.*]], label [[C]]
+; CHECK-NEXT: br i1 [[ARG:%.*]], label [[IF_E:%.*]], label [[C]]
; CHECK: c:
-; CHECK-NEXT: br i1 %arg, label [[IF_G:%.*]], label [[IF_E]]
+; CHECK-NEXT: br i1 [[ARG]], label [[IF_G:%.*]], label [[IF_E]]
; CHECK: if.g:
; CHECK-NEXT: store i32 undef, ptr @a, align 4
; CHECK-NEXT: br label [[WHILE_D]]
diff --git a/llvm/test/Transforms/NewGVN/pr33204.ll b/llvm/test/Transforms/NewGVN/pr33204.ll
index a57544cc7f557..6a76444420f93 100644
--- a/llvm/test/Transforms/NewGVN/pr33204.ll
+++ b/llvm/test/Transforms/NewGVN/pr33204.ll
@@ -24,9 +24,9 @@ define void @hoge(i32 %arg, i1 %arg2) {
; CHECK-NEXT: unreachable
; CHECK: bb6:
; CHECK-NEXT: store i32 [[TMP]], ptr @global.1, align 4, !h [[META0]]
-; CHECK-NEXT: br i1 %arg2, label [[BB7:%.*]], label [[BB1]]
+; CHECK-NEXT: br i1 [[ARG2:%.*]], label [[BB7:%.*]], label [[BB1]]
; CHECK: bb7:
-; CHECK-NEXT: br i1 %arg2, label [[BB10:%.*]], label [[BB8:%.*]]
+; CHECK-NEXT: br i1 [[ARG2]], label [[BB10:%.*]], label [[BB8:%.*]]
; CHECK: bb8:
; CHECK-NEXT: br i1 false, label [[BB9:%.*]], label [[BB3:%.*]]
; CHECK: bb9:
diff --git a/llvm/test/Transforms/NewGVN/pr33720.ll b/llvm/test/Transforms/NewGVN/pr33720.ll
index 5621148a12068..ddd4317a6d2b5 100644
--- a/llvm/test/Transforms/NewGVN/pr33720.ll
+++ b/llvm/test/Transforms/NewGVN/pr33720.ll
@@ -8,11 +8,11 @@
define void @patatino(i1 %arg) {
; CHECK-LABEL: @patatino(
; CHECK-NEXT: entry:
-; CHECK-NEXT: br i1 %arg, label [[IF_END24:%.*]], label [[FOR_COND16:%.*]]
+; CHECK-NEXT: br i1 [[ARG:%.*]], label [[IF_END24:%.*]], label [[FOR_COND16:%.*]]
; CHECK: for.cond2thread-pre-split:
; CHECK-NEXT: br i1 false, label [[FOR_BODY:%.*]], label [[FOR_COND8_PREHEADER:%.*]]
; CHECK: for.cond8.preheader:
-; CHECK-NEXT: br i1 %arg, label [[L1:%.*]], label [[FOR_COND11THREAD_PRE_SPLIT_LR_PH:%.*]]
+; CHECK-NEXT: br i1 [[ARG]], label [[L1:%.*]], label [[FOR_COND11THREAD_PRE_SPLIT_LR_PH:%.*]]
; CHECK: for.cond11thread-pre-split.lr.ph:
; CHECK-NEXT: br label [[L1]]
; CHECK: for.body:
@@ -32,7 +32,7 @@ define void @patatino(i1 %arg) {
; CHECK-NEXT: br label [[FOR_BODY]]
; CHECK: for.cond16:
; CHECK-NEXT: [[J_0:%.*]] = phi ptr [ @f, [[ENTRY:%.*]] ], [ poison, [[FOR_COND20:%.*]] ], [ @e, [[FOR_COND16]] ]
-; CHECK-NEXT: br i1 %arg, label [[FOR_COND20]], label [[FOR_COND16]]
+; CHECK-NEXT: br i1 [[ARG]], label [[FOR_COND20]], label [[FOR_COND16]]
; CHECK: for.cond20:
; CHECK-NEXT: [[J_2:%.*]] = phi ptr [ [[J_0]], [[FOR_COND16]] ], [ poison, [[IF_END24]] ]
; CHECK-NEXT: br i1 true, label [[IF_END24]], label [[FOR_COND16]]
diff --git a/llvm/test/Transforms/Util/PredicateInfo/phi-predicate.ll b/llvm/test/Transforms/Util/PredicateInfo/phi-predicate.ll
new file mode 100644
index 0000000000000..0b001d4e4b8fb
--- /dev/null
+++ b/llvm/test/Transforms/Util/PredicateInfo/phi-predicate.ll
@@ -0,0 +1,43 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -passes=print-predicateinfo < %s 2>&1 >/dev/null | FileCheck %s
+
+ at p = local_unnamed_addr global i32 0
+
+define noundef i32 @h5diff(i32 %0, i1 %1) local_unnamed_addr #0 {
+; CHECK-LABEL: @h5diff(
+; CHECK-NEXT: [[COND:%.*]] = icmp eq i32 [[TMP0:%.*]], 0
+; CHECK-NEXT: br i1 [[TMP1:%.*]], label [[TMP3:%.*]], label [[TMP4:%.*]]
+; CHECK: 3:
+; CHECK-NEXT: store i32 1, ptr @p, align 4
+; CHECK: [[DOT0:%.*]] = bitcast i32 [[TMP0]] to i32
+; CHECK-NEXT: br i1 [[COND]], label [[TMP5:%.*]], label [[COMMON_RET:%.*]]
+; CHECK: common.ret:
+; CHECK-NEXT: ret i32 0
+; CHECK: 4:
+; CHECK-NEXT: store i32 2, ptr @p, align 4
+; CHECK: [[DOT1:%.*]] = bitcast i32 [[TMP0]] to i32
+; CHECK-NEXT: br i1 [[COND]], label [[TMP5]], label [[COMMON_RET]]
+; CHECK: 5:
+; CHECK-NEXT: [[DOTPREDICATE_PHI:%.*]] = phi i32 [ [[DOT1]], [[TMP4]] ], [ [[DOT0]], [[TMP3]] ]
+; CHECK: [[TMP6:%.*]] = bitcast i32 [[TMP0]] to i32
+; CHECK-NEXT: store i32 [[TMP6]], ptr @p, align 4
+; CHECK-NEXT: br label [[COMMON_RET]]
+;
+ %cond = icmp eq i32 %0, 0
+ br i1 %1, label %3, label %4
+
+3:
+ store i32 1, ptr @p, align 4
+ br i1 %cond, label %5, label %common.ret
+
+common.ret:
+ ret i32 0
+
+4:
+ store i32 2, ptr @p, align 4
+ br i1 %cond, label %5, label %common.ret
+
+5:
+ store i32 %0, ptr @p, align 4
+ br label %common.ret
+}
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