From 0d64113d231ea9d0da66b223592a4d5ea695846c Mon Sep 17 00:00:00 2001
From: Akshat Oke <Akshat.Oke@amd.com>
Date: Wed, 26 Mar 2025 08:18:05 +0000
Subject: [PATCH] Stitch in loop passes in codegen pipeline
---
llvm/include/llvm/Passes/CodeGenPassBuilder.h | 16 ++++++++++++++--
llvm/include/llvm/Target/CGPassBuilderOption.h | 2 ++
llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp | 8 +++++++-
3 files changed, 23 insertions(+), 3 deletions(-)
diff --git a/llvm/include/llvm/Passes/CodeGenPassBuilder.h b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
index 61e377de0c424..a1be22cda96c8 100644
--- a/llvm/include/llvm/Passes/CodeGenPassBuilder.h
+++ b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
@@ -107,13 +107,16 @@
#include "llvm/Target/CGPassBuilderOption.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Transforms/CFGuard.h"
+#include "llvm/Transforms/ObjCARC.h"
#include "llvm/Transforms/Scalar/ConstantHoisting.h"
#include "llvm/Transforms/Scalar/LoopPassManager.h"
#include "llvm/Transforms/Scalar/LoopStrengthReduce.h"
+#include "llvm/Transforms/Scalar/LoopTermFold.h"
#include "llvm/Transforms/Scalar/LowerConstantIntrinsics.h"
#include "llvm/Transforms/Scalar/MergeICmps.h"
#include "llvm/Transforms/Scalar/PartiallyInlineLibCalls.h"
#include "llvm/Transforms/Scalar/ScalarizeMaskedMemIntrin.h"
+#include "llvm/Transforms/Utils/CanonicalizeFreezeInLoops.h"
#include "llvm/Transforms/Utils/EntryExitInstrumenter.h"
#include "llvm/Transforms/Utils/LowerInvoke.h"
#include <cassert>
@@ -690,7 +693,12 @@ void CodeGenPassBuilder<Derived, TargetMachineT>::addIRPasses(
// Run loop strength reduction before anything else.
if (getOptLevel() != CodeGenOptLevel::None && !Opt.DisableLSR) {
- addPass(createFunctionToLoopPassAdaptor(LoopStrengthReducePass(),
+ LoopPassManager LPM;
+ LPM.addPass(CanonicalizeFreezeInLoopsPass());
+ LPM.addPass(LoopStrengthReducePass());
+ if (Opt.EnableLoopTermFold)
+ LPM.addPass(LoopTermFoldPass());
+ addPass(createFunctionToLoopPassAdaptor(std::move(LPM),
/*UseMemorySSA=*/true));
}
@@ -735,7 +743,8 @@ void CodeGenPassBuilder<Derived, TargetMachineT>::addIRPasses(
addPass(ScalarizeMaskedMemIntrinPass());
// Expand reduction intrinsics into shuffle sequences if the target wants to.
- addPass(ExpandReductionsPass());
+ if (!Opt.DisableExpandReductions)
+ addPass(ExpandReductionsPass());
// Convert conditional moves to conditional jumps when profitable.
if (getOptLevel() != CodeGenOptLevel::None && !Opt.DisableSelectOptimize)
@@ -810,6 +819,9 @@ void CodeGenPassBuilder<Derived, TargetMachineT>::addISelPrepare(
AddIRPass &addPass) const {
derived().addPreISel(addPass);
+ if (getOptLevel() != CodeGenOptLevel::None)
+ addPass(ObjCARCContractPass());
+
addPass(CallBrPreparePass());
// Add both the safe stack and the stack protection passes: each of them will
// only protect functions that have corresponding attributes.
diff --git a/llvm/include/llvm/Target/CGPassBuilderOption.h b/llvm/include/llvm/Target/CGPassBuilderOption.h
index 51f25c1360b87..00d8a99c3984c 100644
--- a/llvm/include/llvm/Target/CGPassBuilderOption.h
+++ b/llvm/include/llvm/Target/CGPassBuilderOption.h
@@ -51,6 +51,8 @@ struct CGPassBuilderOption {
bool EnableMachineFunctionSplitter = false;
bool EnableSinkAndFold = false;
bool EnableTailMerge = true;
+ /// Enable LoopTermFold immediately after LSR
+ bool EnableLoopTermFold = false;
bool MISchedPostRA = false;
bool EarlyLiveIntervals = false;
bool GCEmptyBlocks = false;
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
index b6cc5137d711a..84efff6fe79be 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
@@ -101,7 +101,9 @@
#include "llvm/Transforms/Scalar/FlattenCFG.h"
#include "llvm/Transforms/Scalar/GVN.h"
#include "llvm/Transforms/Scalar/InferAddressSpaces.h"
+#include "llvm/Transforms/Scalar/LICM.h"
#include "llvm/Transforms/Scalar/LoopDataPrefetch.h"
+#include "llvm/Transforms/Scalar/LoopPassManager.h"
#include "llvm/Transforms/Scalar/NaryReassociate.h"
#include "llvm/Transforms/Scalar/SeparateConstOffsetFromGEP.h"
#include "llvm/Transforms/Scalar/Sink.h"
@@ -2021,7 +2023,11 @@ void AMDGPUCodeGenPassBuilder::addIRPasses(AddIRPass &addPass) const {
// TODO: May want to move later or split into an early and late one.
addPass(AMDGPUCodeGenPreparePass(TM));
- // TODO: LICM
+ // Try to hoist loop invariant parts of divisions AMDGPUCodeGenPrepare may
+ // have expanded.
+ if (TM.getOptLevel() > CodeGenOptLevel::Less)
+ addPass(createFunctionToLoopPassAdaptor(LICMPass(LICMOptions()),
+ /*UseMemorySSA=*/true));
}
Base::addIRPasses(addPass);