[llvm] [AA] Move Target Specific AA before BasicAA (PR #125965)
via llvm-commits
llvm-commits at lists.llvm.org
Tue Mar 11 18:03:01 PDT 2025
https://github.com/Chengjunp updated https://github.com/llvm/llvm-project/pull/125965
>From 749e4bbb3b56569e526dec15a8ceae25d968e6da Mon Sep 17 00:00:00 2001
From: chengjunp <chengjunp at nvidia.com>
Date: Tue, 25 Feb 2025 01:01:29 +0000
Subject: [PATCH 1/4] Add support for moving target specific AA before basic AA
---
llvm/include/llvm/Analysis/AliasAnalysis.h | 2 ++
llvm/include/llvm/Target/TargetMachine.h | 5 +++++
llvm/lib/Analysis/AliasAnalysis.cpp | 10 +++++++---
llvm/lib/Passes/PassBuilderPipelines.cpp | 4 ++++
llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.h | 3 +++
llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp | 2 +-
llvm/lib/Target/NVPTX/NVPTXTargetMachine.h | 2 +-
.../Analysis/NVPTXAA/NVPTXAA_before_BasicAA.ll | 15 +++++++++++++++
8 files changed, 38 insertions(+), 5 deletions(-)
create mode 100644 llvm/test/Analysis/NVPTXAA/NVPTXAA_before_BasicAA.ll
diff --git a/llvm/include/llvm/Analysis/AliasAnalysis.h b/llvm/include/llvm/Analysis/AliasAnalysis.h
index 9c6084d2d9dee..175e16f607e7e 100644
--- a/llvm/include/llvm/Analysis/AliasAnalysis.h
+++ b/llvm/include/llvm/Analysis/AliasAnalysis.h
@@ -993,6 +993,8 @@ struct ExternalAAWrapperPass : ImmutablePass {
explicit ExternalAAWrapperPass(CallbackT CB);
+ virtual bool runEarly() { return false; }
+
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
}
diff --git a/llvm/include/llvm/Target/TargetMachine.h b/llvm/include/llvm/Target/TargetMachine.h
index c3e9d41315f61..588025525d8fe 100644
--- a/llvm/include/llvm/Target/TargetMachine.h
+++ b/llvm/include/llvm/Target/TargetMachine.h
@@ -371,6 +371,11 @@ class TargetMachine {
// TODO: Populate all pass names by using <Target>PassRegistry.def.
virtual void registerPassBuilderCallbacks(PassBuilder &) {}
+ /// Allow the target to register early alias analyses(AA before basicAA) with
+ /// the AAManager for use with the new pass manager. Only affects the
+ /// "default" AAManager.
+ virtual void registerEarlyDefaultAliasAnalyses(AAManager &) {}
+
/// Allow the target to register alias analyses with the AAManager for use
/// with the new pass manager. Only affects the "default" AAManager.
virtual void registerDefaultAliasAnalyses(AAManager &) {}
diff --git a/llvm/lib/Analysis/AliasAnalysis.cpp b/llvm/lib/Analysis/AliasAnalysis.cpp
index 20cdbb6320322..ca7a68b3cbca4 100644
--- a/llvm/lib/Analysis/AliasAnalysis.cpp
+++ b/llvm/lib/Analysis/AliasAnalysis.cpp
@@ -752,6 +752,11 @@ bool AAResultsWrapperPass::runOnFunction(Function &F) {
AAR.reset(
new AAResults(getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F)));
+ // Add any target-specific alias analyses that should be run early.
+ auto *ExtWrapperPass = getAnalysisIfAvailable<ExternalAAWrapperPass>();
+ if (ExtWrapperPass && ExtWrapperPass->runEarly() && ExtWrapperPass->CB)
+ ExtWrapperPass->CB(*this, F, *AAR);
+
// BasicAA is always available for function analyses. Also, we add it first
// so that it can trump TBAA results when it proves MustAlias.
// FIXME: TBAA should have an explicit mode to support this and then we
@@ -771,9 +776,8 @@ bool AAResultsWrapperPass::runOnFunction(Function &F) {
// If available, run an external AA providing callback over the results as
// well.
- if (auto *WrapperPass = getAnalysisIfAvailable<ExternalAAWrapperPass>())
- if (WrapperPass->CB)
- WrapperPass->CB(*this, F, *AAR);
+ if (ExtWrapperPass && !ExtWrapperPass->runEarly() && ExtWrapperPass->CB)
+ ExtWrapperPass->CB(*this, F, *AAR);
// Analyses don't mutate the IR, so return false.
return false;
diff --git a/llvm/lib/Passes/PassBuilderPipelines.cpp b/llvm/lib/Passes/PassBuilderPipelines.cpp
index 17710eb94b6de..0afcf992dcde7 100644
--- a/llvm/lib/Passes/PassBuilderPipelines.cpp
+++ b/llvm/lib/Passes/PassBuilderPipelines.cpp
@@ -2202,6 +2202,10 @@ AAManager PassBuilder::buildDefaultAAPipeline() {
// The order in which these are registered determines their priority when
// being queried.
+ // Add any target-specific alias analyses that should be run early.
+ if (TM)
+ TM->registerEarlyDefaultAliasAnalyses(AA);
+
// First we register the basic alias analysis that provides the majority of
// per-function local AA logic. This is a stateless, on-demand local set of
// AA techniques.
diff --git a/llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.h b/llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.h
index 2d204979eb6ce..e509ef3abe67e 100644
--- a/llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.h
+++ b/llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.h
@@ -79,10 +79,13 @@ class NVPTXAAWrapperPass : public ImmutablePass {
// Wrapper around ExternalAAWrapperPass so that the default
// constructor gets the callback.
+// Note that NVPTXAA will run before BasicAA to for compile time considerations.
class NVPTXExternalAAWrapper : public ExternalAAWrapperPass {
public:
static char ID;
+ bool runEarly() override { return true; }
+
NVPTXExternalAAWrapper()
: ExternalAAWrapperPass([](Pass &P, Function &, AAResults &AAR) {
if (auto *WrapperPass =
diff --git a/llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp b/llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp
index 7d04cf3dc51e6..c6823961a6e80 100644
--- a/llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp
@@ -221,7 +221,7 @@ MachineFunctionInfo *NVPTXTargetMachine::createMachineFunctionInfo(
F, STI);
}
-void NVPTXTargetMachine::registerDefaultAliasAnalyses(AAManager &AAM) {
+void NVPTXTargetMachine::registerEarlyDefaultAliasAnalyses(AAManager &AAM) {
AAM.registerFunctionAnalysis<NVPTXAA>();
}
diff --git a/llvm/lib/Target/NVPTX/NVPTXTargetMachine.h b/llvm/lib/Target/NVPTX/NVPTXTargetMachine.h
index 2b88da67a50f9..bb65a14a8d792 100644
--- a/llvm/lib/Target/NVPTX/NVPTXTargetMachine.h
+++ b/llvm/lib/Target/NVPTX/NVPTXTargetMachine.h
@@ -64,7 +64,7 @@ class NVPTXTargetMachine : public LLVMTargetMachine {
createMachineFunctionInfo(BumpPtrAllocator &Allocator, const Function &F,
const TargetSubtargetInfo *STI) const override;
- void registerDefaultAliasAnalyses(AAManager &AAM) override;
+ void registerEarlyDefaultAliasAnalyses(AAManager &AAM) override;
void registerPassBuilderCallbacks(PassBuilder &PB) override;
diff --git a/llvm/test/Analysis/NVPTXAA/NVPTXAA_before_BasicAA.ll b/llvm/test/Analysis/NVPTXAA/NVPTXAA_before_BasicAA.ll
new file mode 100644
index 0000000000000..f01dae60085ed
--- /dev/null
+++ b/llvm/test/Analysis/NVPTXAA/NVPTXAA_before_BasicAA.ll
@@ -0,0 +1,15 @@
+; RUN: opt -aa-pipeline=default -passes='require<aa>' -debug-pass-manager -disable-output -S < %s 2>&1 | FileCheck %s
+; RUN: opt -O2 -debug-aa -disable-output -S < %s 2>&1 | FileCheck %s --check-prefix=LEGACY
+; LEGACY: NVPTX AA
+; LEGACY-NEXT: Basic Alias Analysis (stateless AA impl)
+
+; In default AA pipeline, NVPTXAA should run before BasicAA to reduce compile time for NVPTX backend
+target triple = "nvptx64-nvidia-cuda"
+
+; CHECK: Running analysis: NVPTXAA on foo
+; CHECK-NEXT: Running analysis: BasicAA on foo
+define void @foo(){
+entry:
+ ret void
+}
+
>From 0b95b09ca02f02241c1e9f23094a44a11bb4f7cf Mon Sep 17 00:00:00 2001
From: chengjunp <chengjunp at nvidia.com>
Date: Wed, 26 Feb 2025 03:11:21 +0000
Subject: [PATCH 2/4] Update test
---
llvm/test/Analysis/NVPTXAA/NVPTXAA_before_BasicAA.ll | 3 ---
1 file changed, 3 deletions(-)
diff --git a/llvm/test/Analysis/NVPTXAA/NVPTXAA_before_BasicAA.ll b/llvm/test/Analysis/NVPTXAA/NVPTXAA_before_BasicAA.ll
index f01dae60085ed..7d980b0e6f807 100644
--- a/llvm/test/Analysis/NVPTXAA/NVPTXAA_before_BasicAA.ll
+++ b/llvm/test/Analysis/NVPTXAA/NVPTXAA_before_BasicAA.ll
@@ -1,7 +1,4 @@
; RUN: opt -aa-pipeline=default -passes='require<aa>' -debug-pass-manager -disable-output -S < %s 2>&1 | FileCheck %s
-; RUN: opt -O2 -debug-aa -disable-output -S < %s 2>&1 | FileCheck %s --check-prefix=LEGACY
-; LEGACY: NVPTX AA
-; LEGACY-NEXT: Basic Alias Analysis (stateless AA impl)
; In default AA pipeline, NVPTXAA should run before BasicAA to reduce compile time for NVPTX backend
target triple = "nvptx64-nvidia-cuda"
>From 4c285abc655771fdb83d4a12114a7fe0729d00d6 Mon Sep 17 00:00:00 2001
From: chengjunp <chengjunp at nvidia.com>
Date: Mon, 3 Mar 2025 23:37:03 +0000
Subject: [PATCH 3/4] Add test for Legacy PM
---
llvm/lib/Analysis/AliasAnalysis.cpp | 28 ++++++++++++++-----
llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.h | 2 ++
llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp | 5 +---
.../NVPTXAA/NVPTXAA_before_BasicAA.ll | 5 ++++
4 files changed, 29 insertions(+), 11 deletions(-)
diff --git a/llvm/lib/Analysis/AliasAnalysis.cpp b/llvm/lib/Analysis/AliasAnalysis.cpp
index 6ac9a3fab6e36..880ecdfdb4562 100644
--- a/llvm/lib/Analysis/AliasAnalysis.cpp
+++ b/llvm/lib/Analysis/AliasAnalysis.cpp
@@ -750,30 +750,44 @@ bool AAResultsWrapperPass::runOnFunction(Function &F) {
// Add any target-specific alias analyses that should be run early.
auto *ExtWrapperPass = getAnalysisIfAvailable<ExternalAAWrapperPass>();
- if (ExtWrapperPass && ExtWrapperPass->runEarly() && ExtWrapperPass->CB)
+ if (ExtWrapperPass && ExtWrapperPass->runEarly() && ExtWrapperPass->CB) {
+ LLVM_DEBUG(dbgs() << "AAResults register Early ExternalAA: " << ExtWrapperPass->getPassName() << "\n");
ExtWrapperPass->CB(*this, F, *AAR);
+ }
// BasicAA is always available for function analyses. Also, we add it first
// so that it can trump TBAA results when it proves MustAlias.
// FIXME: TBAA should have an explicit mode to support this and then we
// should reconsider the ordering here.
- if (!DisableBasicAA)
+ if (!DisableBasicAA) {
+ LLVM_DEBUG(dbgs() << "AAResults register BasicAA\n");
AAR->addAAResult(getAnalysis<BasicAAWrapperPass>().getResult());
+ }
// Populate the results with the currently available AAs.
- if (auto *WrapperPass = getAnalysisIfAvailable<ScopedNoAliasAAWrapperPass>())
+ if (auto *WrapperPass = getAnalysisIfAvailable<ScopedNoAliasAAWrapperPass>()) {
+ LLVM_DEBUG(dbgs() << "AAResults register ScopedNoAliasAA\n");
AAR->addAAResult(WrapperPass->getResult());
- if (auto *WrapperPass = getAnalysisIfAvailable<TypeBasedAAWrapperPass>())
+ }
+ if (auto *WrapperPass = getAnalysisIfAvailable<TypeBasedAAWrapperPass>()) {
+ LLVM_DEBUG(dbgs() << "AAResults register TypeBasedAA\n");
AAR->addAAResult(WrapperPass->getResult());
- if (auto *WrapperPass = getAnalysisIfAvailable<GlobalsAAWrapperPass>())
+ }
+ if (auto *WrapperPass = getAnalysisIfAvailable<GlobalsAAWrapperPass>()) {
+ LLVM_DEBUG(dbgs() << "AAResults register GlobalsAA\n");
AAR->addAAResult(WrapperPass->getResult());
- if (auto *WrapperPass = getAnalysisIfAvailable<SCEVAAWrapperPass>())
+ }
+ if (auto *WrapperPass = getAnalysisIfAvailable<SCEVAAWrapperPass>()) {
+ LLVM_DEBUG(dbgs() << "AAResults register SCEVAA\n");
AAR->addAAResult(WrapperPass->getResult());
+ }
// If available, run an external AA providing callback over the results as
// well.
- if (ExtWrapperPass && !ExtWrapperPass->runEarly() && ExtWrapperPass->CB)
+ if (ExtWrapperPass && !ExtWrapperPass->runEarly() && ExtWrapperPass->CB) {
+ LLVM_DEBUG(dbgs() << "AAResults register Late ExternalAA: " << ExtWrapperPass->getPassName() << "\n");
ExtWrapperPass->CB(*this, F, *AAR);
+ }
// Analyses don't mutate the IR, so return false.
return false;
diff --git a/llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.h b/llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.h
index e509ef3abe67e..b2b6ef7fe733b 100644
--- a/llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.h
+++ b/llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.h
@@ -92,6 +92,8 @@ class NVPTXExternalAAWrapper : public ExternalAAWrapperPass {
P.getAnalysisIfAvailable<NVPTXAAWrapperPass>())
AAR.addAAResult(WrapperPass->getResult());
}) {}
+
+ StringRef getPassName() const override { return "NVPTX Address space based Alias Analysis Wrapper"; }
};
ImmutablePass *createNVPTXAAWrapperPass();
diff --git a/llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp b/llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp
index fb126851f3b5f..539b03edbfb15 100644
--- a/llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp
@@ -360,10 +360,7 @@ void NVPTXPassConfig::addIRPasses() {
disablePass(&RemoveLoadsIntoFakeUsesID);
addPass(createNVPTXAAWrapperPass());
- addPass(createExternalAAWrapperPass([](Pass &P, Function &, AAResults &AAR) {
- if (auto *WrapperPass = P.getAnalysisIfAvailable<NVPTXAAWrapperPass>())
- AAR.addAAResult(WrapperPass->getResult());
- }));
+ addPass(createNVPTXExternalAAWrapperPass());
// NVVMReflectPass is added in addEarlyAsPossiblePasses, so hopefully running
// it here does nothing. But since we need it for correctness when lowering
diff --git a/llvm/test/Analysis/NVPTXAA/NVPTXAA_before_BasicAA.ll b/llvm/test/Analysis/NVPTXAA/NVPTXAA_before_BasicAA.ll
index 7d980b0e6f807..0d16b344e9f66 100644
--- a/llvm/test/Analysis/NVPTXAA/NVPTXAA_before_BasicAA.ll
+++ b/llvm/test/Analysis/NVPTXAA/NVPTXAA_before_BasicAA.ll
@@ -1,10 +1,15 @@
+; REQUIRES: asserts
; RUN: opt -aa-pipeline=default -passes='require<aa>' -debug-pass-manager -disable-output -S < %s 2>&1 | FileCheck %s
+; RUN: llc --debug-only='aa' -o /dev/null %s 2>&1 | FileCheck %s -check-prefix=LEGACY
; In default AA pipeline, NVPTXAA should run before BasicAA to reduce compile time for NVPTX backend
target triple = "nvptx64-nvidia-cuda"
; CHECK: Running analysis: NVPTXAA on foo
; CHECK-NEXT: Running analysis: BasicAA on foo
+
+; LEGACY: AAResults register Early ExternalAA: NVPTX Address space based Alias Analysis Wrapper
+; LEGACY-NEXT: AAResults register BasicAA
define void @foo(){
entry:
ret void
>From 9d9a05ca2aa88f068daa11a7b62dffe39e9fdb60 Mon Sep 17 00:00:00 2001
From: chengjunp <chengjunp at nvidia.com>
Date: Wed, 12 Mar 2025 01:02:09 +0000
Subject: [PATCH 4/4] Format
---
llvm/lib/Analysis/AliasAnalysis.cpp | 9 ++++++---
llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.h | 4 +++-
2 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/llvm/lib/Analysis/AliasAnalysis.cpp b/llvm/lib/Analysis/AliasAnalysis.cpp
index 880ecdfdb4562..913a228f07bd3 100644
--- a/llvm/lib/Analysis/AliasAnalysis.cpp
+++ b/llvm/lib/Analysis/AliasAnalysis.cpp
@@ -751,7 +751,8 @@ bool AAResultsWrapperPass::runOnFunction(Function &F) {
// Add any target-specific alias analyses that should be run early.
auto *ExtWrapperPass = getAnalysisIfAvailable<ExternalAAWrapperPass>();
if (ExtWrapperPass && ExtWrapperPass->runEarly() && ExtWrapperPass->CB) {
- LLVM_DEBUG(dbgs() << "AAResults register Early ExternalAA: " << ExtWrapperPass->getPassName() << "\n");
+ LLVM_DEBUG(dbgs() << "AAResults register Early ExternalAA: "
+ << ExtWrapperPass->getPassName() << "\n");
ExtWrapperPass->CB(*this, F, *AAR);
}
@@ -765,7 +766,8 @@ bool AAResultsWrapperPass::runOnFunction(Function &F) {
}
// Populate the results with the currently available AAs.
- if (auto *WrapperPass = getAnalysisIfAvailable<ScopedNoAliasAAWrapperPass>()) {
+ if (auto *WrapperPass =
+ getAnalysisIfAvailable<ScopedNoAliasAAWrapperPass>()) {
LLVM_DEBUG(dbgs() << "AAResults register ScopedNoAliasAA\n");
AAR->addAAResult(WrapperPass->getResult());
}
@@ -785,7 +787,8 @@ bool AAResultsWrapperPass::runOnFunction(Function &F) {
// If available, run an external AA providing callback over the results as
// well.
if (ExtWrapperPass && !ExtWrapperPass->runEarly() && ExtWrapperPass->CB) {
- LLVM_DEBUG(dbgs() << "AAResults register Late ExternalAA: " << ExtWrapperPass->getPassName() << "\n");
+ LLVM_DEBUG(dbgs() << "AAResults register Late ExternalAA: "
+ << ExtWrapperPass->getPassName() << "\n");
ExtWrapperPass->CB(*this, F, *AAR);
}
diff --git a/llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.h b/llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.h
index b2b6ef7fe733b..f9495517ebfb1 100644
--- a/llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.h
+++ b/llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.h
@@ -93,7 +93,9 @@ class NVPTXExternalAAWrapper : public ExternalAAWrapperPass {
AAR.addAAResult(WrapperPass->getResult());
}) {}
- StringRef getPassName() const override { return "NVPTX Address space based Alias Analysis Wrapper"; }
+ StringRef getPassName() const override {
+ return "NVPTX Address space based Alias Analysis Wrapper";
+ }
};
ImmutablePass *createNVPTXAAWrapperPass();
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