[llvm] 9243841 - Revert "[coro][CoroSplit] Use `llvm.lifetime.end` to compute putting objects on the frame vs the stack (#90265)"
Nikita Popov via llvm-commits
llvm-commits at lists.llvm.org
Mon May 6 17:42:04 PDT 2024
Author: Nikita Popov
Date: 2024-05-07T09:41:25+09:00
New Revision: 924384161ffceda08099536dd07a953299a69b53
URL: https://github.com/llvm/llvm-project/commit/924384161ffceda08099536dd07a953299a69b53
DIFF: https://github.com/llvm/llvm-project/commit/924384161ffceda08099536dd07a953299a69b53.diff
LOG: Revert "[coro][CoroSplit] Use `llvm.lifetime.end` to compute putting objects on the frame vs the stack (#90265)"
This reverts commit fcf341d3ddfe2289ac88aa3c122b25df8732cc8e.
Causes major compile-time regressions when not using coroutines.
Added:
Modified:
llvm/include/llvm/Analysis/CFG.h
llvm/lib/Analysis/CFG.cpp
llvm/lib/Transforms/Coroutines/CoroFrame.cpp
Removed:
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 23bc10a4a9d1ba..86b01c13274fec 100644
--- a/llvm/include/llvm/Analysis/CFG.h
+++ b/llvm/include/llvm/Analysis/CFG.h
@@ -96,18 +96,6 @@ 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 556326406e7ad2..8528aa9f77e022 100644
--- a/llvm/lib/Analysis/CFG.cpp
+++ b/llvm/lib/Analysis/CFG.cpp
@@ -134,21 +134,10 @@ bool llvm::isPotentiallyReachableFromMany(
SmallVectorImpl<BasicBlock *> &Worklist, const BasicBlock *StopBB,
const SmallPtrSetImpl<BasicBlock *> *ExclusionSet, const DominatorTree *DT,
const LoopInfo *LI) {
- return isManyPotentiallyReachableFromMany(
- Worklist, llvm::SmallPtrSet<const BasicBlock *, 1>{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,
+ // When the 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);
+ if (DT && !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.
@@ -166,9 +155,7 @@ bool llvm::isManyPotentiallyReachableFromMany(
}
}
- llvm::DenseMap<const BasicBlock *, const Loop *> StopLoops;
- for (auto *StopBB : StopSet)
- StopLoops[StopBB] = LI ? getOutermostLoop(LI, StopBB) : nullptr;
+ const Loop *StopLoop = LI ? getOutermostLoop(LI, StopBB) : nullptr;
unsigned Limit = DefaultMaxBBsToExplore;
SmallPtrSet<const BasicBlock*, 32> Visited;
@@ -176,13 +163,11 @@ bool llvm::isManyPotentiallyReachableFromMany(
BasicBlock *BB = Worklist.pop_back_val();
if (!Visited.insert(BB).second)
continue;
- if (StopSet.contains(BB))
+ if (BB == StopBB)
return true;
if (ExclusionSet && ExclusionSet->count(BB))
continue;
- if (DT && llvm::any_of(StopSet, [&](const BasicBlock *StopBB) {
- return StopBBReachable[BB] && DT->dominates(BB, StopBB);
- }))
+ if (DT && DT->dominates(BB, StopBB))
return true;
const Loop *Outer = nullptr;
@@ -194,10 +179,7 @@ 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 (StopLoop && Outer == StopLoop)
return true;
}
diff --git a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
index dd9e77a855ef4b..08a4522e3fac6d 100644
--- a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
@@ -19,7 +19,6 @@
#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"
@@ -1441,22 +1440,17 @@ namespace {
struct AllocaUseVisitor : PtrUseVisitor<AllocaUseVisitor> {
using Base = PtrUseVisitor<AllocaUseVisitor>;
AllocaUseVisitor(const DataLayout &DL, const DominatorTree &DT,
- const coro::Shape &CoroShape,
- const SuspendCrossingInfo &Checker,
+ const CoroBeginInst &CB, const SuspendCrossingInfo &Checker,
bool ShouldUseLifetimeStartInfo)
- : PtrUseVisitor(DL), DT(DT), CoroShape(CoroShape), Checker(Checker),
- ShouldUseLifetimeStartInfo(ShouldUseLifetimeStartInfo) {
- for (AnyCoroSuspendInst *SuspendInst : CoroShape.CoroSuspends)
- CoroSuspendBBs.insert(SuspendInst->getParent());
- }
+ : PtrUseVisitor(DL), DT(DT), CoroBegin(CB), Checker(Checker),
+ ShouldUseLifetimeStartInfo(ShouldUseLifetimeStartInfo) {}
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(CoroShape.CoroBegin, PI.getEscapingInst())) {
+ if (PI.isEscaped() && !DT.dominates(&CoroBegin, PI.getEscapingInst())) {
MayWriteBeforeCoroBegin = true;
}
}
@@ -1559,19 +1553,10 @@ 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 (!IsOffsetKnown || !Offset.isZero())
- return Base::visitIntrinsicInst(II);
- switch (II.getIntrinsicID()) {
- default:
+ if (II.getIntrinsicID() != Intrinsic::lifetime_start || !IsOffsetKnown ||
+ !Offset.isZero())
return Base::visitIntrinsicInst(II);
- case Intrinsic::lifetime_start:
- LifetimeStarts.insert(&II);
- LifetimeStartBBs.push_back(II.getParent());
- break;
- case Intrinsic::lifetime_end:
- LifetimeEndBBs.insert(II.getParent());
- break;
- }
+ LifetimeStarts.insert(&II);
}
void visitCallBase(CallBase &CB) {
@@ -1601,7 +1586,7 @@ struct AllocaUseVisitor : PtrUseVisitor<AllocaUseVisitor> {
private:
const DominatorTree &DT;
- const coro::Shape &CoroShape;
+ const CoroBeginInst &CoroBegin;
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
@@ -1609,9 +1594,6 @@ 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};
@@ -1623,19 +1605,10 @@ 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()) {
- // 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;
-
+ for (auto *I : Users)
+ for (auto *S : LifetimeStarts)
+ if (Checker.isDefinitionAcrossSuspend(*S, I))
+ 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
@@ -1673,13 +1646,13 @@ struct AllocaUseVisitor : PtrUseVisitor<AllocaUseVisitor> {
}
void handleMayWrite(const Instruction &I) {
- if (!DT.dominates(CoroShape.CoroBegin, &I))
+ if (!DT.dominates(&CoroBegin, &I))
MayWriteBeforeCoroBegin = true;
}
bool usedAfterCoroBegin(Instruction &I) {
for (auto &U : I.uses())
- if (DT.dominates(CoroShape.CoroBegin, U))
+ if (DT.dominates(&CoroBegin, U))
return true;
return false;
}
@@ -1688,7 +1661,7 @@ 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(CoroShape.CoroBegin, &I) || !usedAfterCoroBegin(I))
+ if (DT.dominates(&CoroBegin, &I) || !usedAfterCoroBegin(I))
return;
if (!IsOffsetKnown) {
@@ -2857,7 +2830,8 @@ 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, Checker,
+ AllocaUseVisitor Visitor{AI->getModule()->getDataLayout(), DT,
+ *Shape.CoroBegin, 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
deleted file mode 100644
index 9a26a722a1e0db..00000000000000
--- a/llvm/test/Transforms/Coroutines/coro-lifetime-end.ll
+++ /dev/null
@@ -1,142 +0,0 @@
-; 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
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