[llvm] 5952972 - [CodeGen][NPM] Port BranchFolder to NPM (#128858)
via llvm-commits
llvm-commits at lists.llvm.org
Thu Mar 13 01:11:32 PDT 2025
Author: Akshat Oke
Date: 2025-03-13T13:41:28+05:30
New Revision: 5952972c9164216be7c22292c52c131f1d0a8030
URL: https://github.com/llvm/llvm-project/commit/5952972c9164216be7c22292c52c131f1d0a8030
DIFF: https://github.com/llvm/llvm-project/commit/5952972c9164216be7c22292c52c131f1d0a8030.diff
LOG: [CodeGen][NPM] Port BranchFolder to NPM (#128858)
EnableTailMerge is false by default and is handled by the pass builder.
Passes are independent of target pipeline options.
This completes the generic `MachineLateOptimization` passes for the NPM
pipeline.
Added:
llvm/include/llvm/CodeGen/BranchFoldingPass.h
Modified:
llvm/include/llvm/InitializePasses.h
llvm/include/llvm/Passes/CodeGenPassBuilder.h
llvm/include/llvm/Passes/MachinePassRegistry.def
llvm/include/llvm/Target/CGPassBuilderOption.h
llvm/lib/CodeGen/BranchFolding.cpp
llvm/lib/CodeGen/CodeGen.cpp
llvm/lib/Passes/PassBuilder.cpp
llvm/test/CodeGen/AArch64/branch-folder-oneinst.mir
llvm/test/CodeGen/AMDGPU/branch-folder-requires-no-phis.mir
llvm/test/CodeGen/Hexagon/branchfolder-insert-impdef.mir
llvm/test/CodeGen/MIR/X86/branch-folder-with-label.mir
llvm/test/CodeGen/X86/branchfolding-ehpad.mir
Removed:
################################################################################
diff --git a/llvm/include/llvm/CodeGen/BranchFoldingPass.h b/llvm/include/llvm/CodeGen/BranchFoldingPass.h
new file mode 100644
index 0000000000000..6ebef47252d25
--- /dev/null
+++ b/llvm/include/llvm/CodeGen/BranchFoldingPass.h
@@ -0,0 +1,31 @@
+//===- llvm/CodeGen/BranchFoldingPass.h -------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_CODEGEN_BRANCHFOLDINGPASS_H
+#define LLVM_CODEGEN_BRANCHFOLDINGPASS_H
+
+#include "llvm/CodeGen/MachinePassManager.h"
+
+namespace llvm {
+
+class BranchFolderPass : public PassInfoMixin<BranchFolderPass> {
+ bool EnableTailMerge;
+
+public:
+ BranchFolderPass(bool EnableTailMerge) : EnableTailMerge(EnableTailMerge) {}
+ PreservedAnalyses run(MachineFunction &MF,
+ MachineFunctionAnalysisManager &MFAM);
+
+ MachineFunctionProperties getRequiredProperties() const {
+ return MachineFunctionProperties().set(
+ MachineFunctionProperties::Property::NoPHIs);
+ }
+};
+
+} // namespace llvm
+
+#endif // LLVM_CODEGEN_BRANCHFOLDINGPASS_H
diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
index 36be3d552f556..78ff93019fd7e 100644
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -59,7 +59,7 @@ void initializeBasicBlockSectionsPass(PassRegistry &);
void initializeBarrierNoopPass(PassRegistry &);
void initializeBasicAAWrapperPassPass(PassRegistry &);
void initializeBlockFrequencyInfoWrapperPassPass(PassRegistry &);
-void initializeBranchFolderPassPass(PassRegistry &);
+void initializeBranchFolderLegacyPass(PassRegistry &);
void initializeBranchProbabilityInfoWrapperPassPass(PassRegistry &);
void initializeBranchRelaxationPass(PassRegistry &);
void initializeBreakCriticalEdgesPass(PassRegistry &);
diff --git a/llvm/include/llvm/Passes/CodeGenPassBuilder.h b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
index 90a0cdf803560..8a2287d797993 100644
--- a/llvm/include/llvm/Passes/CodeGenPassBuilder.h
+++ b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
@@ -23,6 +23,7 @@
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/Analysis/TypeBasedAliasAnalysis.h"
#include "llvm/CodeGen/AssignmentTrackingAnalysis.h"
+#include "llvm/CodeGen/BranchFoldingPass.h"
#include "llvm/CodeGen/CallBrPrepare.h"
#include "llvm/CodeGen/CodeGenPrepare.h"
#include "llvm/CodeGen/DeadMachineInstructionElim.h"
@@ -1205,7 +1206,7 @@ template <typename Derived, typename TargetMachineT>
void CodeGenPassBuilder<Derived, TargetMachineT>::addMachineLateOptimization(
AddMachinePass &addPass) const {
// Branch folding must be run after regalloc and prolog/epilog insertion.
- addPass(BranchFolderPass());
+ addPass(BranchFolderPass(Opt.EnableTailMerge));
// Tail duplication.
// Note that duplicating tail just increases code size and degrades
diff --git a/llvm/include/llvm/Passes/MachinePassRegistry.def b/llvm/include/llvm/Passes/MachinePassRegistry.def
index ebfdaf82169d8..083548d3c78ce 100644
--- a/llvm/include/llvm/Passes/MachinePassRegistry.def
+++ b/llvm/include/llvm/Passes/MachinePassRegistry.def
@@ -195,6 +195,15 @@ MACHINE_FUNCTION_PASS("verify<machine-trace-metrics>", MachineTraceMetricsVerifi
#define MACHINE_FUNCTION_PASS_WITH_PARAMS(NAME, CLASS, CREATE_PASS, PARSER, \
PARAMS)
#endif
+MACHINE_FUNCTION_PASS_WITH_PARAMS(
+ "branch-folder", "BranchFolderPass",
+ [](bool EnableTailMerge) { return BranchFolderPass(EnableTailMerge); },
+ [](StringRef Params) {
+ return parseSinglePassOption(Params, "enable-tail-merge",
+ "BranchFolderPass");
+ },
+ "enable-tail-merge")
+
MACHINE_FUNCTION_PASS_WITH_PARAMS(
"machine-sink", "MachineSinkingPass",
[](bool EnableSinkAndFold) {
@@ -246,7 +255,6 @@ DUMMY_MACHINE_FUNCTION_PASS("bbsections-prepare", BasicBlockSectionsPass)
DUMMY_MACHINE_FUNCTION_PASS("bbsections-profile-reader", BasicBlockSectionsProfileReaderPass)
DUMMY_MACHINE_FUNCTION_PASS("block-placement", MachineBlockPlacementPass)
DUMMY_MACHINE_FUNCTION_PASS("block-placement-stats", MachineBlockPlacementStatsPass)
-DUMMY_MACHINE_FUNCTION_PASS("branch-folder", BranchFolderPass)
DUMMY_MACHINE_FUNCTION_PASS("break-false-deps", BreakFalseDepsPass)
DUMMY_MACHINE_FUNCTION_PASS("cfguard-longjmp", CFGuardLongjmpPass)
DUMMY_MACHINE_FUNCTION_PASS("cfi-fixup", CFIFixupPass)
diff --git a/llvm/include/llvm/Target/CGPassBuilderOption.h b/llvm/include/llvm/Target/CGPassBuilderOption.h
index f006ef1fcb40b..51f25c1360b87 100644
--- a/llvm/include/llvm/Target/CGPassBuilderOption.h
+++ b/llvm/include/llvm/Target/CGPassBuilderOption.h
@@ -50,6 +50,7 @@ struct CGPassBuilderOption {
bool EnableGlobalMergeFunc = false;
bool EnableMachineFunctionSplitter = false;
bool EnableSinkAndFold = false;
+ bool EnableTailMerge = true;
bool MISchedPostRA = false;
bool EarlyLiveIntervals = false;
bool GCEmptyBlocks = false;
diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp
index 5218e39b88222..6f5afbd2a996a 100644
--- a/llvm/lib/CodeGen/BranchFolding.cpp
+++ b/llvm/lib/CodeGen/BranchFolding.cpp
@@ -24,6 +24,7 @@
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/CodeGen/Analysis.h"
+#include "llvm/CodeGen/BranchFoldingPass.h"
#include "llvm/CodeGen/MBFIWrapper.h"
#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
@@ -88,38 +89,62 @@ TailMergeSize("tail-merge-size",
namespace {
/// BranchFolderPass - Wrap branch folder in a machine function pass.
- class BranchFolderPass : public MachineFunctionPass {
- public:
- static char ID;
+class BranchFolderLegacy : public MachineFunctionPass {
+public:
+ static char ID;
- explicit BranchFolderPass(): MachineFunctionPass(ID) {}
+ explicit BranchFolderLegacy() : MachineFunctionPass(ID) {}
- bool runOnMachineFunction(MachineFunction &MF) override;
+ bool runOnMachineFunction(MachineFunction &MF) override;
- void getAnalysisUsage(AnalysisUsage &AU) const override {
- AU.addRequired<MachineBlockFrequencyInfoWrapperPass>();
- AU.addRequired<MachineBranchProbabilityInfoWrapperPass>();
- AU.addRequired<ProfileSummaryInfoWrapperPass>();
- AU.addRequired<TargetPassConfig>();
- MachineFunctionPass::getAnalysisUsage(AU);
- }
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.addRequired<MachineBlockFrequencyInfoWrapperPass>();
+ AU.addRequired<MachineBranchProbabilityInfoWrapperPass>();
+ AU.addRequired<ProfileSummaryInfoWrapperPass>();
+ AU.addRequired<TargetPassConfig>();
+ MachineFunctionPass::getAnalysisUsage(AU);
+ }
- MachineFunctionProperties getRequiredProperties() const override {
- return MachineFunctionProperties().set(
- MachineFunctionProperties::Property::NoPHIs);
- }
- };
+ MachineFunctionProperties getRequiredProperties() const override {
+ return MachineFunctionProperties().set(
+ MachineFunctionProperties::Property::NoPHIs);
+ }
+};
} // end anonymous namespace
-char BranchFolderPass::ID = 0;
-
-char &llvm::BranchFolderPassID = BranchFolderPass::ID;
-
-INITIALIZE_PASS(BranchFolderPass, DEBUG_TYPE,
- "Control Flow Optimizer", false, false)
+char BranchFolderLegacy::ID = 0;
+
+char &llvm::BranchFolderPassID = BranchFolderLegacy::ID;
+
+INITIALIZE_PASS(BranchFolderLegacy, DEBUG_TYPE, "Control Flow Optimizer", false,
+ false)
+
+PreservedAnalyses BranchFolderPass::run(MachineFunction &MF,
+ MachineFunctionAnalysisManager &MFAM) {
+ MFPropsModifier _(*this, MF);
+ bool EnableTailMerge =
+ !MF.getTarget().requiresStructuredCFG() && this->EnableTailMerge;
+
+ auto &MBPI = MFAM.getResult<MachineBranchProbabilityAnalysis>(MF);
+ auto *PSI = MFAM.getResult<ModuleAnalysisManagerMachineFunctionProxy>(MF)
+ .getCachedResult<ProfileSummaryAnalysis>(
+ *MF.getFunction().getParent());
+ if (!PSI)
+ report_fatal_error(
+ "ProfileSummaryAnalysis is required for BranchFoldingPass", false);
+
+ auto &MBFI = MFAM.getResult<MachineBlockFrequencyAnalysis>(MF);
+ MBFIWrapper MBBFreqInfo(MBFI);
+ BranchFolder Folder(EnableTailMerge, /*CommonHoist=*/true, MBBFreqInfo, MBPI,
+ PSI);
+ if (!Folder.OptimizeFunction(MF, MF.getSubtarget().getInstrInfo(),
+ MF.getSubtarget().getRegisterInfo()))
+ return PreservedAnalyses::all();
+ return getMachineFunctionPassPreservedAnalyses();
+}
-bool BranchFolderPass::runOnMachineFunction(MachineFunction &MF) {
+bool BranchFolderLegacy::runOnMachineFunction(MachineFunction &MF) {
if (skipFunction(MF.getFunction()))
return false;
diff --git a/llvm/lib/CodeGen/CodeGen.cpp b/llvm/lib/CodeGen/CodeGen.cpp
index b36d2f743d512..8d108c25e00d9 100644
--- a/llvm/lib/CodeGen/CodeGen.cpp
+++ b/llvm/lib/CodeGen/CodeGen.cpp
@@ -22,7 +22,7 @@ void llvm::initializeCodeGen(PassRegistry &Registry) {
initializeAtomicExpandLegacyPass(Registry);
initializeBasicBlockPathCloningPass(Registry);
initializeBasicBlockSectionsPass(Registry);
- initializeBranchFolderPassPass(Registry);
+ initializeBranchFolderLegacyPass(Registry);
initializeBranchRelaxationPass(Registry);
initializeBreakFalseDepsPass(Registry);
initializeCallBrPreparePass(Registry);
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index 8d1273e3631c3..3d7cf3fefe687 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -80,6 +80,7 @@
#include "llvm/CodeGen/AssignmentTrackingAnalysis.h"
#include "llvm/CodeGen/AtomicExpand.h"
#include "llvm/CodeGen/BasicBlockSectionsProfileReader.h"
+#include "llvm/CodeGen/BranchFoldingPass.h"
#include "llvm/CodeGen/CallBrPrepare.h"
#include "llvm/CodeGen/CodeGenPrepare.h"
#include "llvm/CodeGen/ComplexDeinterleavingPass.h"
diff --git a/llvm/test/CodeGen/AArch64/branch-folder-oneinst.mir b/llvm/test/CodeGen/AArch64/branch-folder-oneinst.mir
index cfb6da3e9ae7a..f1224783c93ea 100644
--- a/llvm/test/CodeGen/AArch64/branch-folder-oneinst.mir
+++ b/llvm/test/CodeGen/AArch64/branch-folder-oneinst.mir
@@ -1,4 +1,5 @@
# RUN: llc -o - %s -mtriple=aarch64 -run-pass branch-folder -verify-machineinstrs | FileCheck %s
+# RUN: llc -o - %s -mtriple=aarch64 -passes="require<profile-summary>,function(machine-function(branch-folder<enable-tail-merge>))" -verify-machineinstrs | FileCheck %s
# Check that BranchFolding pass is able to hoist a common instruction into a block with a single branch instruction.
name: func
tracksRegLiveness: true
diff --git a/llvm/test/CodeGen/AMDGPU/branch-folder-requires-no-phis.mir b/llvm/test/CodeGen/AMDGPU/branch-folder-requires-no-phis.mir
index a5b5098795265..2d6b60e7133ab 100644
--- a/llvm/test/CodeGen/AMDGPU/branch-folder-requires-no-phis.mir
+++ b/llvm/test/CodeGen/AMDGPU/branch-folder-requires-no-phis.mir
@@ -1,9 +1,11 @@
# REQUIRES: asserts
-# RUN: not --crash llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -run-pass=branch-folder -o /dev/null %s 2>&1 | FileCheck %s
+# RUN: not --crash llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -run-pass=branch-folder -o /dev/null %s 2>&1 | FileCheck %s --check-prefixes=LEGACY-CHECK,CHECK
+# RUN: not --crash llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -passes="require<profile-summary>,function(machine-function(branch-folder<enable-tail-merge>))" -o /dev/null %s 2>&1 | FileCheck %s --check-prefixes=NPM-CHECK,CHECK
# BranchFolding breaks this function due to phis
-# CHECK: MachineFunctionProperties required by Control Flow Optimizer pass are not met by function func.
+# LEGACY-CHECK: MachineFunctionProperties required by Control Flow Optimizer pass are not met by function func.
+# NPM-CHECK: MachineFunctionProperties required by BranchFolderPass pass are not met by function func.
# CHECK-NEXT: Required properties: NoPHIs
# CHECK-NEXT: Current properties: IsSSA, TracksLiveness{{$}}
---
diff --git a/llvm/test/CodeGen/Hexagon/branchfolder-insert-impdef.mir b/llvm/test/CodeGen/Hexagon/branchfolder-insert-impdef.mir
index 97f57fcc97e98..5e80432471750 100644
--- a/llvm/test/CodeGen/Hexagon/branchfolder-insert-impdef.mir
+++ b/llvm/test/CodeGen/Hexagon/branchfolder-insert-impdef.mir
@@ -1,4 +1,5 @@
# RUN: llc -mtriple=hexagon -run-pass branch-folder %s -o - -verify-machineinstrs | FileCheck %s
+# RUN: llc -mtriple=hexagon -passes="require<profile-summary>,function(machine-function(branch-folder<enable-tail-merge>))" %s -o - -verify-machineinstrs | FileCheck %s
# Branch folding will perform tail merging of bb.1 and bb.2, and bb.2 will
# become the common tail. The use of R0 in bb.2 is <undef> while the
diff --git a/llvm/test/CodeGen/MIR/X86/branch-folder-with-label.mir b/llvm/test/CodeGen/MIR/X86/branch-folder-with-label.mir
index ce225d4567e91..27737989dcb43 100644
--- a/llvm/test/CodeGen/MIR/X86/branch-folder-with-label.mir
+++ b/llvm/test/CodeGen/MIR/X86/branch-folder-with-label.mir
@@ -39,6 +39,7 @@
# }
#
# RUN: llc -o - %s -mtriple=x86_64-- -run-pass=branch-folder | FileCheck %s
+# RUN: llc -o - %s -mtriple=x86_64-- -passes="require<profile-summary>,function(machine-function(branch-folder<enable-tail-merge>))" | FileCheck %s
--- |
; ModuleID = 'test.ll'
source_filename = "test.ll"
diff --git a/llvm/test/CodeGen/X86/branchfolding-ehpad.mir b/llvm/test/CodeGen/X86/branchfolding-ehpad.mir
index d445cd2068030..e15905c07282d 100644
--- a/llvm/test/CodeGen/X86/branchfolding-ehpad.mir
+++ b/llvm/test/CodeGen/X86/branchfolding-ehpad.mir
@@ -1,4 +1,5 @@
# RUN: llc -mtriple=x86_64-windows-msvc -verify-machineinstrs -run-pass branch-folder -o - %s | FileCheck %s
+# RUN: llc -mtriple=x86_64-windows-msvc -verify-machineinstrs -passes="require<profile-summary>,function(machine-function(branch-folder<enable-tail-merge>))" -o - %s | FileCheck %s
# Check that branch-folder does not create a fallthrough to a landing pad.
# Also make sure that the landing pad still can be tail merged.
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