[llvm] AMDGPU/NewPM: Start filling out addIRPasses (PR #102884)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm updated https://github.com/llvm/llvm-project/pull/102884

>From c564ce0e41c3f7591d547753c33fcdcbbdbcb5ca Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Mon, 12 Aug 2024 15:26:25 +0400
Subject: [PATCH] AMDGPU/NewPM: Start filling out addIRPasses

This is not complete, but gets AtomicExpand running. I was able
to get further than I expected; we're quite close to having all
the IR codegen passes ported.
---
 .../lib/Target/AMDGPU/AMDGPUTargetMachine.cpp | 100 ++++++++++++++++++
 llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h  |   3 +
 2 files changed, 103 insertions(+)

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
index b27746f9d6a55..c89d9ff906d14 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
@@ -65,10 +65,16 @@
 #include "llvm/Transforms/IPO/GlobalDCE.h"
 #include "llvm/Transforms/IPO/Internalize.h"
 #include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Scalar/EarlyCSE.h"
 #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/NaryReassociate.h"
+#include "llvm/Transforms/Scalar/SeparateConstOffsetFromGEP.h"
 #include "llvm/Transforms/Scalar/Sink.h"
+#include "llvm/Transforms/Scalar/StraightLineStrengthReduce.h"
 #include "llvm/Transforms/Scalar/StructurizeCFG.h"
 #include "llvm/Transforms/Utils.h"
 #include "llvm/Transforms/Utils/FixIrreducible.h"
@@ -1769,6 +1775,70 @@ AMDGPUCodeGenPassBuilder::AMDGPUCodeGenPassBuilder(
               ShadowStackGCLoweringPass>();
 }
 
+void AMDGPUCodeGenPassBuilder::addIRPasses(AddIRPass &addPass) const {
+  // TODO: Missing AMDGPURemoveIncompatibleFunctions
+
+  addPass(AMDGPUPrintfRuntimeBindingPass());
+  if (LowerCtorDtor)
+    addPass(AMDGPUCtorDtorLoweringPass());
+
+  if (isPassEnabled(EnableImageIntrinsicOptimizer))
+    addPass(AMDGPUImageIntrinsicOptimizerPass(TM));
+
+  // This can be disabled by passing ::Disable here or on the command line
+  // with --expand-variadics-override=disable.
+  addPass(ExpandVariadicsPass(ExpandVariadicsMode::Lowering));
+
+  addPass(AMDGPUAlwaysInlinePass());
+  addPass(AlwaysInlinerPass());
+
+  // TODO: Missing OpenCLEnqueuedBlockLowering
+
+  // Runs before PromoteAlloca so the latter can account for function uses
+  if (EnableLowerModuleLDS)
+    addPass(AMDGPULowerModuleLDSPass(TM));
+
+  if (TM.getOptLevel() > CodeGenOptLevel::None)
+    addPass(InferAddressSpacesPass());
+
+  // Run atomic optimizer before Atomic Expand
+  if (TM.getOptLevel() >= CodeGenOptLevel::Less &&
+      (AMDGPUAtomicOptimizerStrategy != ScanOptions::None))
+    addPass(AMDGPUAtomicOptimizerPass(TM, AMDGPUAtomicOptimizerStrategy));
+
+  addPass(AtomicExpandPass());
+
+  if (TM.getOptLevel() > CodeGenOptLevel::None) {
+    addPass(AMDGPUPromoteAllocaPass(TM));
+    if (isPassEnabled(EnableScalarIRPasses))
+      addStraightLineScalarOptimizationPasses(addPass);
+
+    // TODO: Handle EnableAMDGPUAliasAnalysis
+
+    // TODO: May want to move later or split into an early and late one.
+    addPass(AMDGPUCodeGenPreparePass(TM));
+
+    // TODO: LICM
+  }
+
+  Base::addIRPasses(addPass);
+
+  // EarlyCSE is not always strong enough to clean up what LSR produces. For
+  // example, GVN can combine
+  //
+  //   %0 = add %a, %b
+  //   %1 = add %b, %a
+  //
+  // and
+  //
+  //   %0 = shl nsw %a, 2
+  //   %1 = shl %a, 2
+  //
+  // but EarlyCSE can do neither of them.
+  if (isPassEnabled(EnableScalarIRPasses))
+    addEarlyCSEOrGVNPass(addPass);
+}
+
 void AMDGPUCodeGenPassBuilder::addCodeGenPrepare(AddIRPass &addPass) const {
   // AMDGPUAnnotateKernelFeaturesPass is missing here, but it will hopefully be
   // deleted soon.
@@ -1875,3 +1945,33 @@ bool AMDGPUCodeGenPassBuilder::isPassEnabled(const cl::opt<bool> &Opt,
     return false;
   return Opt;
 }
+
+void AMDGPUCodeGenPassBuilder::addEarlyCSEOrGVNPass(AddIRPass &addPass) const {
+  if (TM.getOptLevel() == CodeGenOptLevel::Aggressive)
+    addPass(GVNPass());
+  else
+    addPass(EarlyCSEPass());
+}
+
+void AMDGPUCodeGenPassBuilder::addStraightLineScalarOptimizationPasses(
+    AddIRPass &addPass) const {
+  if (isPassEnabled(EnableLoopPrefetch, CodeGenOptLevel::Aggressive))
+    addPass(LoopDataPrefetchPass());
+
+  addPass(SeparateConstOffsetFromGEPPass());
+
+  // ReassociateGEPs exposes more opportunities for SLSR. See
+  // the example in reassociate-geps-and-slsr.ll.
+  addPass(StraightLineStrengthReducePass());
+
+  // SeparateConstOffsetFromGEP and SLSR creates common expressions which GVN or
+  // EarlyCSE can reuse.
+  addEarlyCSEOrGVNPass(addPass);
+
+  // Run NaryReassociate after EarlyCSE/GVN to be more effective.
+  addPass(NaryReassociatePass());
+
+  // NaryReassociate on GEPs creates redundant common expressions, so run
+  // EarlyCSE after it.
+  addPass(EarlyCSEPass());
+}
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h
index 9ee406154b9b7..27ff0da5e812f 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h
@@ -172,6 +172,7 @@ class AMDGPUCodeGenPassBuilder
                            const CGPassBuilderOption &Opts,
                            PassInstrumentationCallbacks *PIC);
 
+  void addIRPasses(AddIRPass &) const;
   void addCodeGenPrepare(AddIRPass &) const;
   void addPreISel(AddIRPass &addPass) const;
   void addAsmPrinter(AddMachinePass &, CreateMCStreamer) const;
@@ -182,6 +183,8 @@ class AMDGPUCodeGenPassBuilder
   /// given that a pass shall work at an optimization \p Level minimum.
   bool isPassEnabled(const cl::opt<bool> &Opt,
                      CodeGenOptLevel Level = CodeGenOptLevel::Default) const;
+  void addEarlyCSEOrGVNPass(AddIRPass &) const;
+  void addStraightLineScalarOptimizationPasses(AddIRPass &) const;
 };
 
 } // end namespace llvm