[llvm] [AMDGPU} Port AMDGPURewriteUndefForPHI to new pass manager (PR #66008)

[via llvm-commits]

llvmbot wrote:

@llvm/pr-subscribers-backend-amdgpu

<details>
<summary>Changes</summary>

This patch ports the AMDGPURewriteUndefForPHI pass to the new pass manager. With this, the pass is supported under both the legacy and the new pass managers.
--
Full diff: https://github.com/llvm/llvm-project/pull/66008.diff

4 Files Affected:

- (modified) llvm/lib/Target/AMDGPU/AMDGPU.h (+10) 
- (modified) llvm/lib/Target/AMDGPU/AMDGPURewriteUndefForPHI.cpp (+14) 
- (modified) llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp (+4) 
- (modified) llvm/test/CodeGen/AMDGPU/rewrite-undef-for-phi.ll (+1) 


<pre>
diff --git a/llvm/lib/Target/AMDGPU/AMDGPU.h b/llvm/lib/Target/AMDGPU/AMDGPU.h
index 157a02ec31b2ec6..434943490caeab3 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPU.h
+++ b/llvm/lib/Target/AMDGPU/AMDGPU.h
@@ -291,6 +291,16 @@ FunctionPass *createAMDGPURewriteUndefForPHIPass();
 void initializeAMDGPURewriteUndefForPHIPass(PassRegistry &);
 extern char &AMDGPURewriteUndefForPHIPassID;
 
+class AMDGPURewriteUndefForPHIPass
+    : public PassInfoMixin<AMDGPURewriteUndefForPHIPass> {
+private:
+  TargetMachine &TM;
+
+public:
+  AMDGPURewriteUndefForPHIPass(TargetMachine &TM) : TM(TM){};
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
+};
+
 void initializeSIAnnotateControlFlowPass(PassRegistry&);
 extern char &SIAnnotateControlFlowPassID;
 
diff --git a/llvm/lib/Target/AMDGPU/AMDGPURewriteUndefForPHI.cpp b/llvm/lib/Target/AMDGPU/AMDGPURewriteUndefForPHI.cpp
index 9c07851243c9173..3e9625e954ea653 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPURewriteUndefForPHI.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPURewriteUndefForPHI.cpp
@@ -177,6 +177,20 @@ bool AMDGPURewriteUndefForPHI::runOnFunction(Function &F) {
   return rewritePHIs(F, UA, DT);
 }
 
+PreservedAnalyses
+AMDGPURewriteUndefForPHIPass::run(Function &F, FunctionAnalysisManager &AM) {
+  UniformityInfo &UA = AM.getResult<UniformityInfoAnalysis>(F);
+  DominatorTree *DT = &AM.getResult<DominatorTreeAnalysis>(F);
+  bool Changed = rewritePHIs(F, UA, DT);
+  if (Changed) {
+    PreservedAnalyses PA;
+    PA.preserveSet<CFGAnalyses>();
+    return PA;
+  }
+
+  return PreservedAnalyses::all();
+}
+
 FunctionPass *llvm::createAMDGPURewriteUndefForPHIPass() {
   return new AMDGPURewriteUndefForPHI();
 }
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
index 991681dafedaad1..befa036ee32df14 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
@@ -663,6 +663,10 @@ void AMDGPUTargetMachine::registerPassBuilderCallbacks(PassBuilder &PB) {
           PM.addPass(AMDGPULowerKernelArgumentsPass(*this));
           return true;
         }
+        if (PassName == "amdgpu-rewrite-undef-for-phi") {
+          PM.addPass(AMDGPURewriteUndefForPHIPass(*this));
+          return true;
+        }
         return false;
       });
 
diff --git a/llvm/test/CodeGen/AMDGPU/rewrite-undef-for-phi.ll b/llvm/test/CodeGen/AMDGPU/rewrite-undef-for-phi.ll
index c0f6c5ae0240a69..4f6b9f474c13171 100644
--- a/llvm/test/CodeGen/AMDGPU/rewrite-undef-for-phi.ll
+++ b/llvm/test/CodeGen/AMDGPU/rewrite-undef-for-phi.ll
@@ -1,5 +1,6 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -mtriple=amdgcn-- -S -amdgpu-rewrite-undef-for-phi %s | FileCheck -check-prefix=OPT %s
+; RUN: opt -mtriple=amdgcn-- -S -passes=amdgpu-rewrite-undef-for-phi %s | FileCheck -check-prefix=OPT %s
 
 define amdgpu_ps float @basic(float inreg %c, i32 %x) #0 {
 ; OPT-LABEL: @basic(
</pre>

</details>

https://github.com/llvm/llvm-project/pull/66008