[llvm] Reapply "[coro][CoroSplit] Use `llvm.lifetime.end` to compute putting objects on the frame vs the stack (#90265) (PR #91372)
Alan Zhao via llvm-commits
llvm-commits at lists.llvm.org
Mon May 13 13:20:24 PDT 2024
https://github.com/alanzhao1 updated https://github.com/llvm/llvm-project/pull/91372
>From e4c029f1f906960416e285231fc3f023b4f1e55c Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Tue, 7 May 2024 11:01:30 -0700
Subject: [PATCH 01/12] Reapply "[coro][CoroSplit] Use `llvm.lifetime.end` to
compute putting objects on the frame vs the stack (#90265)"
This reverts commit 924384161ffceda08099536dd07a953299a69b53.
This reland addresses the performance regressions seen in #90265 by
retaining the original definition of
`isPotentiallyReachableFromMany(...)` instead of reimplementing it with
`isManyPotentiallyReachableFromMany(...)`.
Fixes #86580
---
llvm/include/llvm/Analysis/CFG.h | 12 ++
llvm/lib/Analysis/CFG.cpp | 85 ++++++++++-
llvm/lib/Transforms/Coroutines/CoroFrame.cpp | 60 +++++---
.../Coroutines/coro-lifetime-end.ll | 142 ++++++++++++++++++
4 files changed, 281 insertions(+), 18 deletions(-)
create mode 100644 llvm/test/Transforms/Coroutines/coro-lifetime-end.ll
diff --git a/llvm/include/llvm/Analysis/CFG.h b/llvm/include/llvm/Analysis/CFG.h
index 86b01c13274fe..23bc10a4a9d1b 100644
--- a/llvm/include/llvm/Analysis/CFG.h
+++ b/llvm/include/llvm/Analysis/CFG.h
@@ -96,6 +96,18 @@ bool isPotentiallyReachableFromMany(
const SmallPtrSetImpl<BasicBlock *> *ExclusionSet,
const DominatorTree *DT = nullptr, const LoopInfo *LI = nullptr);
+/// Determine whether there is a potentially a path from at least one block in
+/// 'Worklist' to at least one block in 'StopSet' within a single function
+/// without passing through any of the blocks in 'ExclusionSet'. Returns false
+/// only if we can prove that once any block in 'Worklist' has been reached then
+/// no blocks in 'StopSet' can be executed without passing through any blocks in
+/// 'ExclusionSet'. Conservatively returns true.
+bool isManyPotentiallyReachableFromMany(
+ SmallVectorImpl<BasicBlock *> &Worklist,
+ const SmallPtrSetImpl<const BasicBlock *> &StopSet,
+ const SmallPtrSetImpl<BasicBlock *> *ExclusionSet,
+ const DominatorTree *DT = nullptr, const LoopInfo *LI = nullptr);
+
/// Return true if the control flow in \p RPOTraversal is irreducible.
///
/// This is a generic implementation to detect CFG irreducibility based on loop
diff --git a/llvm/lib/Analysis/CFG.cpp b/llvm/lib/Analysis/CFG.cpp
index 8528aa9f77e02..57fb529fada46 100644
--- a/llvm/lib/Analysis/CFG.cpp
+++ b/llvm/lib/Analysis/CFG.cpp
@@ -158,7 +158,7 @@ bool llvm::isPotentiallyReachableFromMany(
const Loop *StopLoop = LI ? getOutermostLoop(LI, StopBB) : nullptr;
unsigned Limit = DefaultMaxBBsToExplore;
- SmallPtrSet<const BasicBlock*, 32> Visited;
+ SmallPtrSet<const BasicBlock *, 32> Visited;
do {
BasicBlock *BB = Worklist.pop_back_val();
if (!Visited.insert(BB).second)
@@ -204,6 +204,89 @@ bool llvm::isPotentiallyReachableFromMany(
return false;
}
+bool llvm::isManyPotentiallyReachableFromMany(
+ SmallVectorImpl<BasicBlock *> &Worklist,
+ const SmallPtrSetImpl<const BasicBlock *> &StopSet,
+ const SmallPtrSetImpl<BasicBlock *> *ExclusionSet, const DominatorTree *DT,
+ const LoopInfo *LI) {
+ // When a stop block is unreachable, it's dominated from everywhere,
+ // regardless of whether there's a path between the two blocks.
+ llvm::DenseMap<const BasicBlock *, bool> StopBBReachable;
+ for (auto *BB : StopSet)
+ StopBBReachable[BB] = DT && DT->isReachableFromEntry(BB);
+
+ // We can't skip directly from a block that dominates the stop block if the
+ // exclusion block is potentially in between.
+ if (ExclusionSet && !ExclusionSet->empty())
+ DT = nullptr;
+
+ // Normally any block in a loop is reachable from any other block in a loop,
+ // however excluded blocks might partition the body of a loop to make that
+ // untrue.
+ SmallPtrSet<const Loop *, 8> LoopsWithHoles;
+ if (LI && ExclusionSet) {
+ for (auto *BB : *ExclusionSet) {
+ if (const Loop *L = getOutermostLoop(LI, BB))
+ LoopsWithHoles.insert(L);
+ }
+ }
+
+ llvm::DenseMap<const BasicBlock *, const Loop *> StopLoops;
+ for (auto *StopBB : StopSet)
+ StopLoops[StopBB] = LI ? getOutermostLoop(LI, StopBB) : nullptr;
+
+ unsigned Limit = DefaultMaxBBsToExplore;
+ SmallPtrSet<const BasicBlock*, 32> Visited;
+ do {
+ BasicBlock *BB = Worklist.pop_back_val();
+ if (!Visited.insert(BB).second)
+ continue;
+ if (StopSet.contains(BB))
+ return true;
+ if (ExclusionSet && ExclusionSet->count(BB))
+ continue;
+ if (DT && llvm::any_of(StopSet, [&](const BasicBlock *StopBB) {
+ return StopBBReachable[BB] && DT->dominates(BB, StopBB);
+ }))
+ return true;
+
+ const Loop *Outer = nullptr;
+ if (LI) {
+ Outer = getOutermostLoop(LI, BB);
+ // If we're in a loop with a hole, not all blocks in the loop are
+ // reachable from all other blocks. That implies we can't simply jump to
+ // the loop's exit blocks, as that exit might need to pass through an
+ // excluded block. Clear Outer so we process BB's successors.
+ if (LoopsWithHoles.count(Outer))
+ Outer = nullptr;
+ if (llvm::any_of(StopSet, [&](const BasicBlock *StopBB) {
+ const Loop *StopLoop = StopLoops[StopBB];
+ return StopLoop && StopLoop == Outer;
+ }))
+ return true;
+ }
+
+ if (!--Limit) {
+ // We haven't been able to prove it one way or the other. Conservatively
+ // answer true -- that there is potentially a path.
+ return true;
+ }
+
+ if (Outer) {
+ // All blocks in a single loop are reachable from all other blocks. From
+ // any of these blocks, we can skip directly to the exits of the loop,
+ // ignoring any other blocks inside the loop body.
+ Outer->getExitBlocks(Worklist);
+ } else {
+ Worklist.append(succ_begin(BB), succ_end(BB));
+ }
+ } while (!Worklist.empty());
+
+ // We have exhausted all possible paths and are certain that 'To' can not be
+ // reached from 'From'.
+ return false;
+}
+
bool llvm::isPotentiallyReachable(
const BasicBlock *A, const BasicBlock *B,
const SmallPtrSetImpl<BasicBlock *> *ExclusionSet, const DominatorTree *DT,
diff --git a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
index 08a4522e3fac6..dd9e77a855ef4 100644
--- a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
@@ -19,6 +19,7 @@
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/SmallString.h"
+#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/PtrUseVisitor.h"
#include "llvm/Analysis/StackLifetime.h"
#include "llvm/Config/llvm-config.h"
@@ -1440,17 +1441,22 @@ namespace {
struct AllocaUseVisitor : PtrUseVisitor<AllocaUseVisitor> {
using Base = PtrUseVisitor<AllocaUseVisitor>;
AllocaUseVisitor(const DataLayout &DL, const DominatorTree &DT,
- const CoroBeginInst &CB, const SuspendCrossingInfo &Checker,
+ const coro::Shape &CoroShape,
+ const SuspendCrossingInfo &Checker,
bool ShouldUseLifetimeStartInfo)
- : PtrUseVisitor(DL), DT(DT), CoroBegin(CB), Checker(Checker),
- ShouldUseLifetimeStartInfo(ShouldUseLifetimeStartInfo) {}
+ : PtrUseVisitor(DL), DT(DT), CoroShape(CoroShape), Checker(Checker),
+ ShouldUseLifetimeStartInfo(ShouldUseLifetimeStartInfo) {
+ for (AnyCoroSuspendInst *SuspendInst : CoroShape.CoroSuspends)
+ CoroSuspendBBs.insert(SuspendInst->getParent());
+ }
void visit(Instruction &I) {
Users.insert(&I);
Base::visit(I);
// If the pointer is escaped prior to CoroBegin, we have to assume it would
// be written into before CoroBegin as well.
- if (PI.isEscaped() && !DT.dominates(&CoroBegin, PI.getEscapingInst())) {
+ if (PI.isEscaped() &&
+ !DT.dominates(CoroShape.CoroBegin, PI.getEscapingInst())) {
MayWriteBeforeCoroBegin = true;
}
}
@@ -1553,10 +1559,19 @@ struct AllocaUseVisitor : PtrUseVisitor<AllocaUseVisitor> {
// When we found the lifetime markers refers to a
// subrange of the original alloca, ignore the lifetime
// markers to avoid misleading the analysis.
- if (II.getIntrinsicID() != Intrinsic::lifetime_start || !IsOffsetKnown ||
- !Offset.isZero())
+ if (!IsOffsetKnown || !Offset.isZero())
+ return Base::visitIntrinsicInst(II);
+ switch (II.getIntrinsicID()) {
+ default:
return Base::visitIntrinsicInst(II);
- LifetimeStarts.insert(&II);
+ case Intrinsic::lifetime_start:
+ LifetimeStarts.insert(&II);
+ LifetimeStartBBs.push_back(II.getParent());
+ break;
+ case Intrinsic::lifetime_end:
+ LifetimeEndBBs.insert(II.getParent());
+ break;
+ }
}
void visitCallBase(CallBase &CB) {
@@ -1586,7 +1601,7 @@ struct AllocaUseVisitor : PtrUseVisitor<AllocaUseVisitor> {
private:
const DominatorTree &DT;
- const CoroBeginInst &CoroBegin;
+ const coro::Shape &CoroShape;
const SuspendCrossingInfo &Checker;
// All alias to the original AllocaInst, created before CoroBegin and used
// after CoroBegin. Each entry contains the instruction and the offset in the
@@ -1594,6 +1609,9 @@ struct AllocaUseVisitor : PtrUseVisitor<AllocaUseVisitor> {
DenseMap<Instruction *, std::optional<APInt>> AliasOffetMap{};
SmallPtrSet<Instruction *, 4> Users{};
SmallPtrSet<IntrinsicInst *, 2> LifetimeStarts{};
+ SmallVector<BasicBlock *> LifetimeStartBBs{};
+ SmallPtrSet<BasicBlock *, 2> LifetimeEndBBs{};
+ SmallPtrSet<const BasicBlock *, 2> CoroSuspendBBs{};
bool MayWriteBeforeCoroBegin{false};
bool ShouldUseLifetimeStartInfo{true};
@@ -1605,10 +1623,19 @@ struct AllocaUseVisitor : PtrUseVisitor<AllocaUseVisitor> {
// every basic block that uses the pointer to see if they cross suspension
// points. The uses cover both direct uses as well as indirect uses.
if (ShouldUseLifetimeStartInfo && !LifetimeStarts.empty()) {
- for (auto *I : Users)
- for (auto *S : LifetimeStarts)
- if (Checker.isDefinitionAcrossSuspend(*S, I))
- return true;
+ // If there is no explicit lifetime.end, then assume the address can
+ // cross suspension points.
+ if (LifetimeEndBBs.empty())
+ return true;
+
+ // If there is a path from a lifetime.start to a suspend without a
+ // corresponding lifetime.end, then the alloca's lifetime persists
+ // beyond that suspension point and the alloca must go on the frame.
+ llvm::SmallVector<BasicBlock *> Worklist(LifetimeStartBBs);
+ if (isManyPotentiallyReachableFromMany(Worklist, CoroSuspendBBs,
+ &LifetimeEndBBs, &DT))
+ return true;
+
// Addresses are guaranteed to be identical after every lifetime.start so
// we cannot use the local stack if the address escaped and there is a
// suspend point between lifetime markers. This should also cover the
@@ -1646,13 +1673,13 @@ struct AllocaUseVisitor : PtrUseVisitor<AllocaUseVisitor> {
}
void handleMayWrite(const Instruction &I) {
- if (!DT.dominates(&CoroBegin, &I))
+ if (!DT.dominates(CoroShape.CoroBegin, &I))
MayWriteBeforeCoroBegin = true;
}
bool usedAfterCoroBegin(Instruction &I) {
for (auto &U : I.uses())
- if (DT.dominates(&CoroBegin, U))
+ if (DT.dominates(CoroShape.CoroBegin, U))
return true;
return false;
}
@@ -1661,7 +1688,7 @@ struct AllocaUseVisitor : PtrUseVisitor<AllocaUseVisitor> {
// We track all aliases created prior to CoroBegin but used after.
// These aliases may need to be recreated after CoroBegin if the alloca
// need to live on the frame.
- if (DT.dominates(&CoroBegin, &I) || !usedAfterCoroBegin(I))
+ if (DT.dominates(CoroShape.CoroBegin, &I) || !usedAfterCoroBegin(I))
return;
if (!IsOffsetKnown) {
@@ -2830,8 +2857,7 @@ static void collectFrameAlloca(AllocaInst *AI, coro::Shape &Shape,
bool ShouldUseLifetimeStartInfo =
(Shape.ABI != coro::ABI::Async && Shape.ABI != coro::ABI::Retcon &&
Shape.ABI != coro::ABI::RetconOnce);
- AllocaUseVisitor Visitor{AI->getModule()->getDataLayout(), DT,
- *Shape.CoroBegin, Checker,
+ AllocaUseVisitor Visitor{AI->getModule()->getDataLayout(), DT, Shape, Checker,
ShouldUseLifetimeStartInfo};
Visitor.visitPtr(*AI);
if (!Visitor.getShouldLiveOnFrame())
diff --git a/llvm/test/Transforms/Coroutines/coro-lifetime-end.ll b/llvm/test/Transforms/Coroutines/coro-lifetime-end.ll
new file mode 100644
index 0000000000000..330c61360e20a
--- /dev/null
+++ b/llvm/test/Transforms/Coroutines/coro-lifetime-end.ll
@@ -0,0 +1,142 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt < %s -passes='cgscc(coro-split),simplifycfg,early-cse' -S | FileCheck %s
+
+declare ptr @malloc(i64)
+
+%i8.array = type { [100 x i8] }
+declare void @consume.i8.array(ptr)
+
+ at testbool = external local_unnamed_addr global i8, align 1
+
+; testval does not contain an explicit lifetime end. We must assume that it may
+; live across suspension.
+define void @HasNoLifetimeEnd() presplitcoroutine {
+; CHECK-LABEL: define void @HasNoLifetimeEnd() {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ID:%.*]] = call token @llvm.coro.id(i32 0, ptr null, ptr null, ptr @HasNoLifetimeEnd.resumers)
+; CHECK-NEXT: [[ALLOC:%.*]] = call ptr @malloc(i64 16)
+; CHECK-NEXT: [[VFRAME:%.*]] = call noalias nonnull ptr @llvm.coro.begin(token [[ID]], ptr [[ALLOC]])
+; CHECK-NEXT: store ptr @HasNoLifetimeEnd.resume, ptr [[VFRAME]], align 8
+; CHECK-NEXT: [[DESTROY_ADDR:%.*]] = getelementptr inbounds [[HASNOLIFETIMEEND_FRAME:%.*]], ptr [[VFRAME]], i32 0, i32 1
+; CHECK-NEXT: store ptr @HasNoLifetimeEnd.destroy, ptr [[DESTROY_ADDR]], align 8
+; CHECK-NEXT: [[INDEX_ADDR1:%.*]] = getelementptr inbounds [[HASNOLIFETIMEEND_FRAME]], ptr [[VFRAME]], i32 0, i32 2
+; CHECK-NEXT: call void @consume.i8.array(ptr [[INDEX_ADDR1]])
+; CHECK-NEXT: [[INDEX_ADDR2:%.*]] = getelementptr inbounds [[HASNOLIFETIMEEND_FRAME]], ptr [[VFRAME]], i32 0, i32 3
+; CHECK-NEXT: store i1 false, ptr [[INDEX_ADDR2]], align 1
+; CHECK-NEXT: ret void
+;
+entry:
+ %testval = alloca %i8.array
+ %id = call token @llvm.coro.id(i32 0, ptr null, ptr null, ptr null)
+ %alloc = call ptr @malloc(i64 16) #3
+ %vFrame = call noalias nonnull ptr @llvm.coro.begin(token %id, ptr %alloc)
+
+ call void @llvm.lifetime.start.p0(i64 100, ptr %testval)
+ call void @consume.i8.array(ptr %testval)
+
+ %save = call token @llvm.coro.save(ptr null)
+ %suspend = call i8 @llvm.coro.suspend(token %save, i1 false)
+ switch i8 %suspend, label %exit [
+ i8 0, label %await.ready
+ i8 1, label %exit
+ ]
+await.ready:
+ br label %exit
+exit:
+ call i1 @llvm.coro.end(ptr null, i1 false, token none)
+ ret void
+}
+
+define void @LifetimeEndAfterCoroEnd() presplitcoroutine {
+; CHECK-LABEL: define void @LifetimeEndAfterCoroEnd() {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ID:%.*]] = call token @llvm.coro.id(i32 0, ptr null, ptr null, ptr @LifetimeEndAfterCoroEnd.resumers)
+; CHECK-NEXT: [[ALLOC:%.*]] = call ptr @malloc(i64 16)
+; CHECK-NEXT: [[VFRAME:%.*]] = call noalias nonnull ptr @llvm.coro.begin(token [[ID]], ptr [[ALLOC]])
+; CHECK-NEXT: store ptr @LifetimeEndAfterCoroEnd.resume, ptr [[VFRAME]], align 8
+; CHECK-NEXT: [[DESTROY_ADDR:%.*]] = getelementptr inbounds [[LIFETIMEENDAFTERCOROEND_FRAME:%.*]], ptr [[VFRAME]], i32 0, i32 1
+; CHECK-NEXT: store ptr @LifetimeEndAfterCoroEnd.destroy, ptr [[DESTROY_ADDR]], align 8
+; CHECK-NEXT: [[INDEX_ADDR1:%.*]] = getelementptr inbounds [[LIFETIMEENDAFTERCOROEND_FRAME]], ptr [[VFRAME]], i32 0, i32 2
+; CHECK-NEXT: call void @consume.i8.array(ptr [[INDEX_ADDR1]])
+; CHECK-NEXT: [[INDEX_ADDR2:%.*]] = getelementptr inbounds [[LIFETIMEENDAFTERCOROEND_FRAME]], ptr [[VFRAME]], i32 0, i32 3
+; CHECK-NEXT: store i1 false, ptr [[INDEX_ADDR2]], align 1
+; CHECK-NEXT: ret void
+;
+entry:
+ %testval = alloca %i8.array
+ %id = call token @llvm.coro.id(i32 0, ptr null, ptr null, ptr null)
+ %alloc = call ptr @malloc(i64 16) #3
+ %vFrame = call noalias nonnull ptr @llvm.coro.begin(token %id, ptr %alloc)
+
+ call void @llvm.lifetime.start.p0(i64 100, ptr %testval)
+ call void @consume.i8.array(ptr %testval)
+
+ %save = call token @llvm.coro.save(ptr null)
+ %suspend = call i8 @llvm.coro.suspend(token %save, i1 false)
+ switch i8 %suspend, label %exit [
+ i8 0, label %await.ready
+ i8 1, label %exit
+ ]
+await.ready:
+ br label %exit
+exit:
+ call i1 @llvm.coro.end(ptr null, i1 false, token none)
+ call void @llvm.lifetime.end.p0(i64 100, ptr %testval)
+ ret void
+}
+
+define void @BranchWithoutLifetimeEnd() presplitcoroutine {
+; CHECK-LABEL: define void @BranchWithoutLifetimeEnd() {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ID:%.*]] = call token @llvm.coro.id(i32 0, ptr null, ptr null, ptr @BranchWithoutLifetimeEnd.resumers)
+; CHECK-NEXT: [[ALLOC:%.*]] = call ptr @malloc(i64 16)
+; CHECK-NEXT: [[VFRAME:%.*]] = call noalias nonnull ptr @llvm.coro.begin(token [[ID]], ptr [[ALLOC]])
+; CHECK-NEXT: store ptr @BranchWithoutLifetimeEnd.resume, ptr [[VFRAME]], align 8
+; CHECK-NEXT: [[DESTROY_ADDR:%.*]] = getelementptr inbounds [[BRANCHWITHOUTLIFETIMEEND_FRAME:%.*]], ptr [[VFRAME]], i32 0, i32 1
+; CHECK-NEXT: store ptr @BranchWithoutLifetimeEnd.destroy, ptr [[DESTROY_ADDR]], align 8
+; CHECK-NEXT: [[TESTVAL:%.*]] = getelementptr inbounds [[BRANCHWITHOUTLIFETIMEEND_FRAME]], ptr [[VFRAME]], i32 0, i32 2
+; CHECK-NEXT: call void @consume.i8.array(ptr [[TESTVAL]])
+; CHECK-NEXT: [[TMP0:%.*]] = load i8, ptr @testbool, align 1
+; CHECK-NEXT: [[INDEX_ADDR1:%.*]] = getelementptr inbounds [[BRANCHWITHOUTLIFETIMEEND_FRAME]], ptr [[VFRAME]], i32 0, i32 3
+; CHECK-NEXT: store i1 false, ptr [[INDEX_ADDR1]], align 1
+; CHECK-NEXT: ret void
+;
+entry:
+ %testval = alloca %i8.array
+ %id = call token @llvm.coro.id(i32 0, ptr null, ptr null, ptr null)
+ %alloc = call ptr @malloc(i64 16) #3
+ %vFrame = call noalias nonnull ptr @llvm.coro.begin(token %id, ptr %alloc)
+
+ call void @llvm.lifetime.start.p0(i64 100, ptr %testval)
+ call void @consume.i8.array(ptr %testval)
+
+ %0 = load i8, ptr @testbool, align 1
+ %tobool = trunc nuw i8 %0 to i1
+ br i1 %tobool, label %if.then, label %if.end
+
+if.then:
+ call void @llvm.lifetime.end.p0(i64 100, ptr %testval)
+ br label %if.end
+
+if.end:
+ %save = call token @llvm.coro.save(ptr null)
+ %suspend = call i8 @llvm.coro.suspend(token %save, i1 false)
+ switch i8 %suspend, label %exit [
+ i8 0, label %await.ready
+ i8 1, label %exit
+ ]
+await.ready:
+ br label %exit
+exit:
+ call i1 @llvm.coro.end(ptr null, i1 false, token none)
+ ret void
+}
+
+
+declare token @llvm.coro.id(i32, ptr readnone, ptr nocapture readonly, ptr)
+declare ptr @llvm.coro.begin(token, ptr writeonly) #3
+declare ptr @llvm.coro.frame() #5
+declare i8 @llvm.coro.suspend(token, i1) #3
+declare i1 @llvm.coro.end(ptr, i1, token) #3
+declare void @llvm.lifetime.start.p0(i64, ptr nocapture) #4
+declare void @llvm.lifetime.end.p0(i64, ptr nocapture) #4
>From 703081b9b7d8f92d281c616a830a3c2a6c927d42 Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Tue, 7 May 2024 11:30:50 -0700
Subject: [PATCH 02/12] fix clang format issue
---
llvm/lib/Analysis/CFG.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/lib/Analysis/CFG.cpp b/llvm/lib/Analysis/CFG.cpp
index 57fb529fada46..6c62e14ec9c85 100644
--- a/llvm/lib/Analysis/CFG.cpp
+++ b/llvm/lib/Analysis/CFG.cpp
@@ -236,7 +236,7 @@ bool llvm::isManyPotentiallyReachableFromMany(
StopLoops[StopBB] = LI ? getOutermostLoop(LI, StopBB) : nullptr;
unsigned Limit = DefaultMaxBBsToExplore;
- SmallPtrSet<const BasicBlock*, 32> Visited;
+ SmallPtrSet<const BasicBlock *, 32> Visited;
do {
BasicBlock *BB = Worklist.pop_back_val();
if (!Visited.insert(BB).second)
>From 0bfa097c578cf731732873aaa52ce9cfaaa0bedd Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Tue, 7 May 2024 15:04:49 -0700
Subject: [PATCH 03/12] Use SmallPtrSet instead of DenseMap
---
llvm/lib/Analysis/CFG.cpp | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/llvm/lib/Analysis/CFG.cpp b/llvm/lib/Analysis/CFG.cpp
index 6c62e14ec9c85..52709bcf8125d 100644
--- a/llvm/lib/Analysis/CFG.cpp
+++ b/llvm/lib/Analysis/CFG.cpp
@@ -211,9 +211,11 @@ bool llvm::isManyPotentiallyReachableFromMany(
const LoopInfo *LI) {
// When a stop block is unreachable, it's dominated from everywhere,
// regardless of whether there's a path between the two blocks.
- llvm::DenseMap<const BasicBlock *, bool> StopBBReachable;
- for (auto *BB : StopSet)
- StopBBReachable[BB] = DT && DT->isReachableFromEntry(BB);
+ SmallPtrSet<const BasicBlock *, 32> StopBBReachable;
+ for (auto *BB : StopSet) {
+ if (DT && DT->isReachableFromEntry(BB))
+ StopBBReachable.insert(BB);
+ }
// We can't skip directly from a block that dominates the stop block if the
// exclusion block is potentially in between.
@@ -246,7 +248,7 @@ bool llvm::isManyPotentiallyReachableFromMany(
if (ExclusionSet && ExclusionSet->count(BB))
continue;
if (DT && llvm::any_of(StopSet, [&](const BasicBlock *StopBB) {
- return StopBBReachable[BB] && DT->dominates(BB, StopBB);
+ return StopBBReachable.contains(BB) && DT->dominates(BB, StopBB);
}))
return true;
>From 025f2369684b928f682a1179161d58fbaa209c17 Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Tue, 7 May 2024 20:02:01 -0700
Subject: [PATCH 04/12] remove extra change
---
llvm/lib/Analysis/CFG.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/lib/Analysis/CFG.cpp b/llvm/lib/Analysis/CFG.cpp
index 52709bcf8125d..17def19c86447 100644
--- a/llvm/lib/Analysis/CFG.cpp
+++ b/llvm/lib/Analysis/CFG.cpp
@@ -158,7 +158,7 @@ bool llvm::isPotentiallyReachableFromMany(
const Loop *StopLoop = LI ? getOutermostLoop(LI, StopBB) : nullptr;
unsigned Limit = DefaultMaxBBsToExplore;
- SmallPtrSet<const BasicBlock *, 32> Visited;
+ SmallPtrSet<const BasicBlock*, 32> Visited;
do {
BasicBlock *BB = Worklist.pop_back_val();
if (!Visited.insert(BB).second)
>From 7e9695fbb8d2316a0a83b7a10457743074948c11 Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Tue, 7 May 2024 20:20:57 -0700
Subject: [PATCH 05/12] use SmallPtrSet for loops
Also make curly braces more consistent
---
llvm/lib/Analysis/CFG.cpp | 22 +++++++++-------------
1 file changed, 9 insertions(+), 13 deletions(-)
diff --git a/llvm/lib/Analysis/CFG.cpp b/llvm/lib/Analysis/CFG.cpp
index 17def19c86447..f943220f0ff51 100644
--- a/llvm/lib/Analysis/CFG.cpp
+++ b/llvm/lib/Analysis/CFG.cpp
@@ -212,10 +212,9 @@ bool llvm::isManyPotentiallyReachableFromMany(
// When a stop block is unreachable, it's dominated from everywhere,
// regardless of whether there's a path between the two blocks.
SmallPtrSet<const BasicBlock *, 32> StopBBReachable;
- for (auto *BB : StopSet) {
+ for (auto *BB : StopSet)
if (DT && DT->isReachableFromEntry(BB))
StopBBReachable.insert(BB);
- }
// We can't skip directly from a block that dominates the stop block if the
// exclusion block is potentially in between.
@@ -226,16 +225,16 @@ bool llvm::isManyPotentiallyReachableFromMany(
// however excluded blocks might partition the body of a loop to make that
// untrue.
SmallPtrSet<const Loop *, 8> LoopsWithHoles;
- if (LI && ExclusionSet) {
- for (auto *BB : *ExclusionSet) {
+ if (LI && ExclusionSet)
+ for (auto *BB : *ExclusionSet)
if (const Loop *L = getOutermostLoop(LI, BB))
LoopsWithHoles.insert(L);
- }
- }
- llvm::DenseMap<const BasicBlock *, const Loop *> StopLoops;
- for (auto *StopBB : StopSet)
- StopLoops[StopBB] = LI ? getOutermostLoop(LI, StopBB) : nullptr;
+ SmallPtrSet<const Loop *, 8> StopLoops;
+ if (LI)
+ for (auto *StopBB : StopSet)
+ if (const Loop *L = getOutermostLoop(LI, StopBB))
+ StopLoops.insert(L);
unsigned Limit = DefaultMaxBBsToExplore;
SmallPtrSet<const BasicBlock *, 32> Visited;
@@ -261,10 +260,7 @@ bool llvm::isManyPotentiallyReachableFromMany(
// excluded block. Clear Outer so we process BB's successors.
if (LoopsWithHoles.count(Outer))
Outer = nullptr;
- if (llvm::any_of(StopSet, [&](const BasicBlock *StopBB) {
- const Loop *StopLoop = StopLoops[StopBB];
- return StopLoop && StopLoop == Outer;
- }))
+ if (StopLoops.contains(Outer))
return true;
}
>From edbcf9fd0020f4a63222baa441179d90420d8c0a Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Tue, 7 May 2024 23:02:42 -0700
Subject: [PATCH 06/12] deduplicate code by using templates
---
llvm/lib/Analysis/CFG.cpp | 167 ++++++++++++++++++--------------------
1 file changed, 78 insertions(+), 89 deletions(-)
diff --git a/llvm/lib/Analysis/CFG.cpp b/llvm/lib/Analysis/CFG.cpp
index f943220f0ff51..9f1ae9ce1ce3a 100644
--- a/llvm/lib/Analysis/CFG.cpp
+++ b/llvm/lib/Analysis/CFG.cpp
@@ -130,14 +130,35 @@ static const Loop *getOutermostLoop(const LoopInfo *LI, const BasicBlock *BB) {
return L ? L->getOutermostLoop() : nullptr;
}
-bool llvm::isPotentiallyReachableFromMany(
- SmallVectorImpl<BasicBlock *> &Worklist, const BasicBlock *StopBB,
- const SmallPtrSetImpl<BasicBlock *> *ExclusionSet, const DominatorTree *DT,
- const LoopInfo *LI) {
- // When the stop block is unreachable, it's dominated from everywhere,
+template <class T, bool IsMany>
+static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
+ const T *StopBBOrSet,
+ const SmallPtrSetImpl<BasicBlock *> *ExclusionSet,
+ const DominatorTree *DT, const LoopInfo *LI) {
+ const BasicBlock *StopBB;
+ const SmallPtrSetImpl<const BasicBlock *> *StopSet;
+
+ // SmallPtrSetImpl is incompatible with LLVM's casting functions.
+ if constexpr (IsMany)
+ StopSet =
+ static_cast<const SmallPtrSetImpl<const BasicBlock *> *>(StopBBOrSet);
+ else
+ StopBB = static_cast<const BasicBlock *>(StopBBOrSet);
+
+ // When a stop block is unreachable, it's dominated from everywhere,
// regardless of whether there's a path between the two blocks.
- if (DT && !DT->isReachableFromEntry(StopBB))
- DT = nullptr;
+ SmallPtrSet<const BasicBlock *, 32> StopBBReachable;
+ if (DT) {
+ if constexpr (IsMany) {
+ for (auto *BB : *StopSet) {
+ if (DT->isReachableFromEntry(BB))
+ StopBBReachable.insert(BB);
+ }
+ } else {
+ if (!DT->isReachableFromEntry(StopBB))
+ DT = nullptr;
+ }
+ }
// We can't skip directly from a block that dominates the stop block if the
// exclusion block is potentially in between.
@@ -155,20 +176,47 @@ bool llvm::isPotentiallyReachableFromMany(
}
}
- const Loop *StopLoop = LI ? getOutermostLoop(LI, StopBB) : nullptr;
+ const Loop *StopLoop = nullptr;
+ SmallPtrSet<const Loop *, 8> StopLoops;
+
+ if constexpr (IsMany) {
+ if (LI) {
+ for (auto *StopSetBB : *StopSet) {
+ if (const Loop *L = getOutermostLoop(LI, StopSetBB))
+ StopLoops.insert(L);
+ }
+ }
+ } else {
+ if (LI)
+ StopLoop = getOutermostLoop(LI, StopBB);
+ }
unsigned Limit = DefaultMaxBBsToExplore;
- SmallPtrSet<const BasicBlock*, 32> Visited;
+ SmallPtrSet<const BasicBlock *, 32> Visited;
do {
BasicBlock *BB = Worklist.pop_back_val();
if (!Visited.insert(BB).second)
continue;
- if (BB == StopBB)
- return true;
+ if constexpr (IsMany) {
+ if (StopSet->contains(BB))
+ return true;
+ } else {
+ if (BB == StopBB)
+ return true;
+ }
if (ExclusionSet && ExclusionSet->count(BB))
continue;
- if (DT && DT->dominates(BB, StopBB))
- return true;
+ if (DT) {
+ if constexpr (IsMany) {
+ if (llvm::any_of(*StopSet, [&](const BasicBlock *StopBB) {
+ return StopBBReachable.contains(BB) && DT->dominates(BB, StopBB);
+ }))
+ return true;
+ } else {
+ if (DT->dominates(BB, StopBB))
+ return true;
+ }
+ }
const Loop *Outer = nullptr;
if (LI) {
@@ -179,8 +227,13 @@ bool llvm::isPotentiallyReachableFromMany(
// excluded block. Clear Outer so we process BB's successors.
if (LoopsWithHoles.count(Outer))
Outer = nullptr;
- if (StopLoop && Outer == StopLoop)
- return true;
+ if constexpr (IsMany) {
+ if (StopLoops.contains(Outer))
+ return true;
+ } else {
+ if (StopLoop && Outer == StopLoop)
+ return true;
+ }
}
if (!--Limit) {
@@ -204,85 +257,21 @@ bool llvm::isPotentiallyReachableFromMany(
return false;
}
+bool llvm::isPotentiallyReachableFromMany(
+ SmallVectorImpl<BasicBlock *> &Worklist, const BasicBlock *StopBB,
+ const SmallPtrSetImpl<BasicBlock *> *ExclusionSet, const DominatorTree *DT,
+ const LoopInfo *LI) {
+ return isReachableImpl<BasicBlock, false>(Worklist, StopBB, ExclusionSet, DT,
+ LI);
+}
+
bool llvm::isManyPotentiallyReachableFromMany(
SmallVectorImpl<BasicBlock *> &Worklist,
const SmallPtrSetImpl<const BasicBlock *> &StopSet,
const SmallPtrSetImpl<BasicBlock *> *ExclusionSet, const DominatorTree *DT,
const LoopInfo *LI) {
- // When a stop block is unreachable, it's dominated from everywhere,
- // regardless of whether there's a path between the two blocks.
- SmallPtrSet<const BasicBlock *, 32> StopBBReachable;
- for (auto *BB : StopSet)
- if (DT && DT->isReachableFromEntry(BB))
- StopBBReachable.insert(BB);
-
- // We can't skip directly from a block that dominates the stop block if the
- // exclusion block is potentially in between.
- if (ExclusionSet && !ExclusionSet->empty())
- DT = nullptr;
-
- // Normally any block in a loop is reachable from any other block in a loop,
- // however excluded blocks might partition the body of a loop to make that
- // untrue.
- SmallPtrSet<const Loop *, 8> LoopsWithHoles;
- if (LI && ExclusionSet)
- for (auto *BB : *ExclusionSet)
- if (const Loop *L = getOutermostLoop(LI, BB))
- LoopsWithHoles.insert(L);
-
- SmallPtrSet<const Loop *, 8> StopLoops;
- if (LI)
- for (auto *StopBB : StopSet)
- if (const Loop *L = getOutermostLoop(LI, StopBB))
- StopLoops.insert(L);
-
- unsigned Limit = DefaultMaxBBsToExplore;
- SmallPtrSet<const BasicBlock *, 32> Visited;
- do {
- BasicBlock *BB = Worklist.pop_back_val();
- if (!Visited.insert(BB).second)
- continue;
- if (StopSet.contains(BB))
- return true;
- if (ExclusionSet && ExclusionSet->count(BB))
- continue;
- if (DT && llvm::any_of(StopSet, [&](const BasicBlock *StopBB) {
- return StopBBReachable.contains(BB) && DT->dominates(BB, StopBB);
- }))
- return true;
-
- const Loop *Outer = nullptr;
- if (LI) {
- Outer = getOutermostLoop(LI, BB);
- // If we're in a loop with a hole, not all blocks in the loop are
- // reachable from all other blocks. That implies we can't simply jump to
- // the loop's exit blocks, as that exit might need to pass through an
- // excluded block. Clear Outer so we process BB's successors.
- if (LoopsWithHoles.count(Outer))
- Outer = nullptr;
- if (StopLoops.contains(Outer))
- return true;
- }
-
- if (!--Limit) {
- // We haven't been able to prove it one way or the other. Conservatively
- // answer true -- that there is potentially a path.
- return true;
- }
-
- if (Outer) {
- // All blocks in a single loop are reachable from all other blocks. From
- // any of these blocks, we can skip directly to the exits of the loop,
- // ignoring any other blocks inside the loop body.
- Outer->getExitBlocks(Worklist);
- } else {
- Worklist.append(succ_begin(BB), succ_end(BB));
- }
- } while (!Worklist.empty());
-
- // We have exhausted all possible paths and are certain that 'To' can not be
- // reached from 'From'.
- return false;
+ return isReachableImpl<SmallPtrSetImpl<const BasicBlock *>, true>(
+ Worklist, &StopSet, ExclusionSet, DT, LI);
}
bool llvm::isPotentiallyReachable(
>From 6dcb05ceb74a73f22edd4483e3bfc3c79ff3866a Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Tue, 7 May 2024 23:07:23 -0700
Subject: [PATCH 07/12] remove unnecessary change..again
---
llvm/lib/Analysis/CFG.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/lib/Analysis/CFG.cpp b/llvm/lib/Analysis/CFG.cpp
index 9f1ae9ce1ce3a..e65de04612810 100644
--- a/llvm/lib/Analysis/CFG.cpp
+++ b/llvm/lib/Analysis/CFG.cpp
@@ -192,7 +192,7 @@ static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
}
unsigned Limit = DefaultMaxBBsToExplore;
- SmallPtrSet<const BasicBlock *, 32> Visited;
+ SmallPtrSet<const BasicBlock*, 32> Visited;
do {
BasicBlock *BB = Worklist.pop_back_val();
if (!Visited.insert(BB).second)
>From ca09dd020e6ad994223fba1b30baf50e101c3aa2 Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Tue, 7 May 2024 23:12:51 -0700
Subject: [PATCH 08/12] reduce size of StopBBReachable to align with size of
CoroSuspendBBs
---
llvm/lib/Analysis/CFG.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/lib/Analysis/CFG.cpp b/llvm/lib/Analysis/CFG.cpp
index e65de04612810..8fa9c42d2b748 100644
--- a/llvm/lib/Analysis/CFG.cpp
+++ b/llvm/lib/Analysis/CFG.cpp
@@ -147,7 +147,7 @@ static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
// When a stop block is unreachable, it's dominated from everywhere,
// regardless of whether there's a path between the two blocks.
- SmallPtrSet<const BasicBlock *, 32> StopBBReachable;
+ SmallPtrSet<const BasicBlock *, 2> StopBBReachable;
if (DT) {
if constexpr (IsMany) {
for (auto *BB : *StopSet) {
>From cbb5c8bf3f712bce6ac9f1fedf3c31f378b92a82 Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Tue, 7 May 2024 23:31:55 -0700
Subject: [PATCH 09/12] ditto with StopLoops
---
llvm/lib/Analysis/CFG.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/lib/Analysis/CFG.cpp b/llvm/lib/Analysis/CFG.cpp
index 8fa9c42d2b748..f6866bfe22499 100644
--- a/llvm/lib/Analysis/CFG.cpp
+++ b/llvm/lib/Analysis/CFG.cpp
@@ -177,7 +177,7 @@ static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
}
const Loop *StopLoop = nullptr;
- SmallPtrSet<const Loop *, 8> StopLoops;
+ SmallPtrSet<const Loop *, 2> StopLoops;
if constexpr (IsMany) {
if (LI) {
>From 3f47dd417adffa45cfbf45c3a9d72a9f58112a36 Mon Sep 17 00:00:00 2001
From: Alan Zhao <azhao101 at gmail.com>
Date: Wed, 8 May 2024 19:28:22 -0700
Subject: [PATCH 10/12] Improve template parameter names
Co-authored-by: Chuanqi Xu <yedeng.yd at linux.alibaba.com>
---
llvm/lib/Analysis/CFG.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/lib/Analysis/CFG.cpp b/llvm/lib/Analysis/CFG.cpp
index f6866bfe22499..f838b0c6dce8d 100644
--- a/llvm/lib/Analysis/CFG.cpp
+++ b/llvm/lib/Analysis/CFG.cpp
@@ -130,7 +130,7 @@ static const Loop *getOutermostLoop(const LoopInfo *LI, const BasicBlock *BB) {
return L ? L->getOutermostLoop() : nullptr;
}
-template <class T, bool IsMany>
+template <class StopT, bool IsManyStop>
static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
const T *StopBBOrSet,
const SmallPtrSetImpl<BasicBlock *> *ExclusionSet,
>From 6a8909cb6d38bb92bedb324fdb9526441f8e7558 Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Wed, 8 May 2024 20:11:00 -0700
Subject: [PATCH 11/12] fix build failure
---
llvm/lib/Analysis/CFG.cpp | 21 ++++++++++-----------
1 file changed, 10 insertions(+), 11 deletions(-)
diff --git a/llvm/lib/Analysis/CFG.cpp b/llvm/lib/Analysis/CFG.cpp
index f838b0c6dce8d..8568547a520ee 100644
--- a/llvm/lib/Analysis/CFG.cpp
+++ b/llvm/lib/Analysis/CFG.cpp
@@ -132,14 +132,14 @@ static const Loop *getOutermostLoop(const LoopInfo *LI, const BasicBlock *BB) {
template <class StopT, bool IsManyStop>
static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
- const T *StopBBOrSet,
+ const StopT *StopBBOrSet,
const SmallPtrSetImpl<BasicBlock *> *ExclusionSet,
const DominatorTree *DT, const LoopInfo *LI) {
const BasicBlock *StopBB;
const SmallPtrSetImpl<const BasicBlock *> *StopSet;
// SmallPtrSetImpl is incompatible with LLVM's casting functions.
- if constexpr (IsMany)
+ if constexpr (IsManyStop)
StopSet =
static_cast<const SmallPtrSetImpl<const BasicBlock *> *>(StopBBOrSet);
else
@@ -149,7 +149,7 @@ static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
// regardless of whether there's a path between the two blocks.
SmallPtrSet<const BasicBlock *, 2> StopBBReachable;
if (DT) {
- if constexpr (IsMany) {
+ if constexpr (IsManyStop) {
for (auto *BB : *StopSet) {
if (DT->isReachableFromEntry(BB))
StopBBReachable.insert(BB);
@@ -179,16 +179,15 @@ static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
const Loop *StopLoop = nullptr;
SmallPtrSet<const Loop *, 2> StopLoops;
- if constexpr (IsMany) {
- if (LI) {
+ if (LI) {
+ if constexpr (IsManyStop) {
for (auto *StopSetBB : *StopSet) {
if (const Loop *L = getOutermostLoop(LI, StopSetBB))
StopLoops.insert(L);
}
- }
- } else {
- if (LI)
+ } else {
StopLoop = getOutermostLoop(LI, StopBB);
+ }
}
unsigned Limit = DefaultMaxBBsToExplore;
@@ -197,7 +196,7 @@ static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
BasicBlock *BB = Worklist.pop_back_val();
if (!Visited.insert(BB).second)
continue;
- if constexpr (IsMany) {
+ if constexpr (IsManyStop) {
if (StopSet->contains(BB))
return true;
} else {
@@ -207,7 +206,7 @@ static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
if (ExclusionSet && ExclusionSet->count(BB))
continue;
if (DT) {
- if constexpr (IsMany) {
+ if constexpr (IsManyStop) {
if (llvm::any_of(*StopSet, [&](const BasicBlock *StopBB) {
return StopBBReachable.contains(BB) && DT->dominates(BB, StopBB);
}))
@@ -227,7 +226,7 @@ static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
// excluded block. Clear Outer so we process BB's successors.
if (LoopsWithHoles.count(Outer))
Outer = nullptr;
- if constexpr (IsMany) {
+ if constexpr (IsManyStop) {
if (StopLoops.contains(Outer))
return true;
} else {
>From a487d326299929c14e3be6540658bfa0d92f7b73 Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Mon, 13 May 2024 13:19:58 -0700
Subject: [PATCH 12/12] create and use SingleEntrySet
---
llvm/lib/Analysis/CFG.cpp | 93 ++++++++++++++++-----------------------
1 file changed, 39 insertions(+), 54 deletions(-)
diff --git a/llvm/lib/Analysis/CFG.cpp b/llvm/lib/Analysis/CFG.cpp
index 8568547a520ee..e5fe79a1ecb75 100644
--- a/llvm/lib/Analysis/CFG.cpp
+++ b/llvm/lib/Analysis/CFG.cpp
@@ -130,33 +130,18 @@ static const Loop *getOutermostLoop(const LoopInfo *LI, const BasicBlock *BB) {
return L ? L->getOutermostLoop() : nullptr;
}
-template <class StopT, bool IsManyStop>
+template <class StopSetT, bool IsManyStop>
static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
- const StopT *StopBBOrSet,
+ const StopSetT &StopSet,
const SmallPtrSetImpl<BasicBlock *> *ExclusionSet,
const DominatorTree *DT, const LoopInfo *LI) {
- const BasicBlock *StopBB;
- const SmallPtrSetImpl<const BasicBlock *> *StopSet;
-
- // SmallPtrSetImpl is incompatible with LLVM's casting functions.
- if constexpr (IsManyStop)
- StopSet =
- static_cast<const SmallPtrSetImpl<const BasicBlock *> *>(StopBBOrSet);
- else
- StopBB = static_cast<const BasicBlock *>(StopBBOrSet);
-
// When a stop block is unreachable, it's dominated from everywhere,
// regardless of whether there's a path between the two blocks.
SmallPtrSet<const BasicBlock *, 2> StopBBReachable;
if (DT) {
- if constexpr (IsManyStop) {
- for (auto *BB : *StopSet) {
- if (DT->isReachableFromEntry(BB))
- StopBBReachable.insert(BB);
- }
- } else {
- if (!DT->isReachableFromEntry(StopBB))
- DT = nullptr;
+ for (auto *BB : StopSet) {
+ if (DT->isReachableFromEntry(BB))
+ StopBBReachable.insert(BB);
}
}
@@ -176,17 +161,12 @@ static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
}
}
- const Loop *StopLoop = nullptr;
SmallPtrSet<const Loop *, 2> StopLoops;
if (LI) {
- if constexpr (IsManyStop) {
- for (auto *StopSetBB : *StopSet) {
- if (const Loop *L = getOutermostLoop(LI, StopSetBB))
- StopLoops.insert(L);
- }
- } else {
- StopLoop = getOutermostLoop(LI, StopBB);
+ for (auto *StopSetBB : StopSet) {
+ if (const Loop *L = getOutermostLoop(LI, StopSetBB))
+ StopLoops.insert(L);
}
}
@@ -196,25 +176,15 @@ static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
BasicBlock *BB = Worklist.pop_back_val();
if (!Visited.insert(BB).second)
continue;
- if constexpr (IsManyStop) {
- if (StopSet->contains(BB))
- return true;
- } else {
- if (BB == StopBB)
- return true;
- }
+ if (StopSet.contains(BB))
+ return true;
if (ExclusionSet && ExclusionSet->count(BB))
continue;
if (DT) {
- if constexpr (IsManyStop) {
- if (llvm::any_of(*StopSet, [&](const BasicBlock *StopBB) {
- return StopBBReachable.contains(BB) && DT->dominates(BB, StopBB);
- }))
- return true;
- } else {
- if (DT->dominates(BB, StopBB))
- return true;
- }
+ if (llvm::any_of(StopSet, [&](const BasicBlock *StopBB) {
+ return StopBBReachable.contains(BB) && DT->dominates(BB, StopBB);
+ }))
+ return true;
}
const Loop *Outer = nullptr;
@@ -226,13 +196,8 @@ static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
// excluded block. Clear Outer so we process BB's successors.
if (LoopsWithHoles.count(Outer))
Outer = nullptr;
- if constexpr (IsManyStop) {
- if (StopLoops.contains(Outer))
- return true;
- } else {
- if (StopLoop && Outer == StopLoop)
- return true;
- }
+ if (StopLoops.contains(Outer))
+ return true;
}
if (!--Limit) {
@@ -256,12 +221,32 @@ static bool isReachableImpl(SmallVectorImpl<BasicBlock *> &Worklist,
return false;
}
+template <class T> class SingleEntrySet {
+public:
+ using iterator = T *;
+ using const_iterator = const T *;
+
+ SingleEntrySet(T Elem) : Elem(Elem) {}
+
+ bool contains(T Other) const { return Elem == Other; }
+
+ iterator begin() { return &Elem; }
+ iterator end() { return &Elem + 1; }
+
+ const_iterator begin() const { return &Elem; }
+ const_iterator end() const { return &Elem + 1; }
+
+private:
+ T Elem;
+};
+
bool llvm::isPotentiallyReachableFromMany(
SmallVectorImpl<BasicBlock *> &Worklist, const BasicBlock *StopBB,
const SmallPtrSetImpl<BasicBlock *> *ExclusionSet, const DominatorTree *DT,
const LoopInfo *LI) {
- return isReachableImpl<BasicBlock, false>(Worklist, StopBB, ExclusionSet, DT,
- LI);
+ return isReachableImpl<SingleEntrySet<const BasicBlock *>, false>(
+ Worklist, SingleEntrySet<const BasicBlock *>(StopBB), ExclusionSet, DT,
+ LI);
}
bool llvm::isManyPotentiallyReachableFromMany(
@@ -270,7 +255,7 @@ bool llvm::isManyPotentiallyReachableFromMany(
const SmallPtrSetImpl<BasicBlock *> *ExclusionSet, const DominatorTree *DT,
const LoopInfo *LI) {
return isReachableImpl<SmallPtrSetImpl<const BasicBlock *>, true>(
- Worklist, &StopSet, ExclusionSet, DT, LI);
+ Worklist, StopSet, ExclusionSet, DT, LI);
}
bool llvm::isPotentiallyReachable(
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