[llvm] wip: Stitch in IR passes in codegen pipeline (PR #133050)

[Akshat Oke via llvm-commits]

https://github.com/optimisan created https://github.com/llvm/llvm-project/pull/133050

None

>From 9aa8daa17e84da2899a2a809e621c5d5ccdfb5b8 Mon Sep 17 00:00:00 2001
From: Akshat Oke <Akshat.Oke at amd.com>
Date: Wed, 26 Mar 2025 08:18:05 +0000
Subject: [PATCH] wip: Stitch in IR passes in codegen pipeline

---
 llvm/include/llvm/Passes/CodeGenPassBuilder.h  | 16 ++++++++++++++--
 llvm/include/llvm/Target/CGPassBuilderOption.h |  2 ++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/llvm/include/llvm/Passes/CodeGenPassBuilder.h b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
index bdb81cf77cfd1..d90b41859d3ba 100644
--- a/llvm/include/llvm/Passes/CodeGenPassBuilder.h
+++ b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
@@ -102,13 +102,16 @@
 #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>
@@ -685,7 +688,12 @@ 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));
   }
 
@@ -730,7 +738,8 @@ 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)
@@ -805,6 +814,9 @@ 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;