[llvm] [CodeGen][NPM] Do not add required passes to pipeline (PR #135752)

[Akshat Oke via llvm-commits]

https://github.com/optimisan updated https://github.com/llvm/llvm-project/pull/135752

>From 0f634cbafba198be3a499121e764fec8d7b8979a Mon Sep 17 00:00:00 2001
From: Akshat Oke <Akshat.Oke at amd.com>
Date: Tue, 15 Apr 2025 06:34:55 +0000
Subject: [PATCH 1/2] [CodeGen][NPM] Do not add required passes to pipeline

---
 llvm/include/llvm/Passes/CodeGenPassBuilder.h | 8 +-------
 llvm/test/tools/llc/new-pm/pipeline.mir       | 2 ++
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/llvm/include/llvm/Passes/CodeGenPassBuilder.h b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
index d092049022623..98c95ca520b0b 100644
--- a/llvm/include/llvm/Passes/CodeGenPassBuilder.h
+++ b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
@@ -183,9 +183,6 @@ template <typename DerivedT, typename TargetMachineT> class CodeGenPassBuilder {
   }
 
 protected:
-  template <typename PassT>
-  using has_required_t = decltype(std::declval<PassT &>().isRequired());
-
   template <typename PassT>
   using is_module_pass_t = decltype(std::declval<PassT &>().run(
       std::declval<Module &>(), std::declval<ModuleAnalysisManager &>()));
@@ -216,10 +213,7 @@ template <typename DerivedT, typename TargetMachineT> class CodeGenPassBuilder {
       static_assert((is_detected<is_function_pass_t, PassT>::value ||
                      is_detected<is_module_pass_t, PassT>::value) &&
                     "Only module pass and function pass are supported.");
-      bool Required = false;
-      if constexpr (is_detected<has_required_t, PassT>::value)
-        Required = PassT::isRequired();
-      if (!PB.runBeforeAdding(Name) && !Required)
+      if (!PB.runBeforeAdding(Name))
         return;
 
       // Add Function Pass
diff --git a/llvm/test/tools/llc/new-pm/pipeline.mir b/llvm/test/tools/llc/new-pm/pipeline.mir
index 761a3a424ee67..8f8e443923b7b 100644
--- a/llvm/test/tools/llc/new-pm/pipeline.mir
+++ b/llvm/test/tools/llc/new-pm/pipeline.mir
@@ -1,8 +1,10 @@
 # RUN: llc -mtriple=x86_64-pc-linux-gnu -x mir -passes=no-op-machine-function --print-pipeline-passes -filetype=null < %s | FileCheck %s --match-full-lines
 # RUN: llc -mtriple=x86_64-pc-linux-gnu -x mir -passes='require<machine-dom-tree>,print<machine-dom-tree>' -print-pipeline-passes < %s | FileCheck --check-prefix=ANALYSIS %s
+# RUN: llc -mtriple=x86_64-pc-linux-gnu -x mir -enable-new-pm -stop-before=greedy -O3 -filetype=null --print-pipeline-passes < %s | FileCheck %s --check-prefix=CHECK-REQ
 
 # CHECK: function(machine-function(no-op-machine-function)),PrintMIRPreparePass,function(machine-function(verify,print))
 
+# CHECK-REQ-NOT: greedy
 # ANALYSIS: require<machine-dom-tree>,print<machine-dom-tree>
 
 ---

>From 33d6bcf5582e790ab49def9818ea13b6a621e191 Mon Sep 17 00:00:00 2001
From: Akshat Oke <Akshat.Oke at amd.com>
Date: Tue, 22 Apr 2025 05:20:31 +0000
Subject: [PATCH 2/2] fix required analyses

---
 llvm/include/llvm/Passes/CodeGenPassBuilder.h  | 14 +++++++++-----
 llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp |  3 ++-
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/llvm/include/llvm/Passes/CodeGenPassBuilder.h b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
index 98c95ca520b0b..e0445dc75a8bf 100644
--- a/llvm/include/llvm/Passes/CodeGenPassBuilder.h
+++ b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
@@ -209,11 +209,12 @@ template <typename DerivedT, typename TargetMachineT> class CodeGenPassBuilder {
     }
 
     template <typename PassT>
-    void operator()(PassT &&Pass, StringRef Name = PassT::name()) {
+    void operator()(PassT &&Pass, bool Force = false,
+                    StringRef Name = PassT::name()) {
       static_assert((is_detected<is_function_pass_t, PassT>::value ||
                      is_detected<is_module_pass_t, PassT>::value) &&
                     "Only module pass and function pass are supported.");
-      if (!PB.runBeforeAdding(Name))
+      if (!Force && !PB.runBeforeAdding(Name))
         return;
 
       // Add Function Pass
@@ -561,9 +562,12 @@ Error CodeGenPassBuilder<Derived, TargetMachineT>::buildPipeline(
 
   {
     AddIRPass addIRPass(MPM, derived());
-    addIRPass(RequireAnalysisPass<MachineModuleAnalysis, Module>());
-    addIRPass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>());
-    addIRPass(RequireAnalysisPass<CollectorMetadataAnalysis, Module>());
+    addIRPass(RequireAnalysisPass<MachineModuleAnalysis, Module>(),
+              /*Force=*/true);
+    addIRPass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>(),
+              /*Force=*/true);
+    addIRPass(RequireAnalysisPass<CollectorMetadataAnalysis, Module>(),
+              /*Force=*/true);
     addISelPasses(addIRPass);
   }
 
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
index 90e3489ced923..029f81a890ae5 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
@@ -2115,7 +2115,8 @@ void AMDGPUCodeGenPassBuilder::addPreISel(AddIRPass &addPass) const {
 
   // FIXME: Why isn't this queried as required from AMDGPUISelDAGToDAG, and why
   // isn't this in addInstSelector?
-  addPass(RequireAnalysisPass<UniformityInfoAnalysis, Function>());
+  addPass(RequireAnalysisPass<UniformityInfoAnalysis, Function>(),
+          /*Force=*/true);
 }
 
 void AMDGPUCodeGenPassBuilder::addILPOpts(AddMachinePass &addPass) const {