[AMDGPU] Use UniformityAnalysis in RewriteUndefsForPHI

Reviewed By: foad

Differential Revision: https://reviews.llvm.org/D145359

llvm/lib/Target/AMDGPU/AMDGPURewriteUndefForPHI.cpp

@@ -10,7 +10,7 @@
 // StructurizedCFG pass, and this pass has some additional limitation that make
 // it can only run after SIAnnotateControlFlow.
 //
-// To achieve optimal code generation for AMDGPU, we assume that divergence
+// To achieve optimal code generation for AMDGPU, we assume that uniformity
 // analysis reports the PHI in join block of divergent branch as uniform if
 // it has one unique uniform value plus additional undefined/poisoned incoming
 // value. That is to say the later compiler pipeline will ensure such PHI always
@@ -56,7 +56,7 @@
 // \---
 
 #include "AMDGPU.h"
-#include "llvm/Analysis/LegacyDivergenceAnalysis.h"
+#include "llvm/Analysis/UniformityAnalysis.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/Dominators.h"
@@ -81,11 +81,11 @@ class AMDGPURewriteUndefForPHI : public FunctionPass {
   }
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {
-    AU.addRequired<LegacyDivergenceAnalysis>();
+    AU.addRequired<UniformityInfoWrapperPass>();
     AU.addRequired<DominatorTreeWrapperPass>();
 
     AU.addPreserved<DominatorTreeWrapperPass>();
-    AU.addPreserved<LegacyDivergenceAnalysis>();
+    AU.addPreserved<UniformityInfoWrapperPass>();
     AU.setPreservesCFG();
   }
 };
@@ -95,17 +95,17 @@ char AMDGPURewriteUndefForPHI::ID = 0;
 
 INITIALIZE_PASS_BEGIN(AMDGPURewriteUndefForPHI, DEBUG_TYPE,
                       "Rewrite undef for PHI", false, false)
-INITIALIZE_PASS_DEPENDENCY(LegacyDivergenceAnalysis)
+INITIALIZE_PASS_DEPENDENCY(UniformityInfoWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
 INITIALIZE_PASS_END(AMDGPURewriteUndefForPHI, DEBUG_TYPE,
                     "Rewrite undef for PHI", false, false)
 
-bool rewritePHIs(Function &F, LegacyDivergenceAnalysis *DA, DominatorTree *DT) {
+bool rewritePHIs(Function &F, UniformityInfo &UA, DominatorTree *DT) {
   bool Changed = false;
   SmallVector<PHINode *> ToBeDeleted;
   for (auto &BB : F) {
     for (auto &PHI : BB.phis()) {
-      if (DA->isDivergent(&PHI))
+      if (UA.isDivergent(&PHI))
         continue;
 
       // The unique incoming value except undef/poison for the PHI node.
@@ -147,7 +147,7 @@ bool rewritePHIs(Function &F, LegacyDivergenceAnalysis *DA, DominatorTree *DT) {
       // TODO: We should still be able to replace undef value if the unique
       // value is a Constant.
       if (!UniqueDefinedIncoming || Undefs.empty() ||
-          !DA->isDivergent(DominateBB->getTerminator()))
+          !UA.isDivergent(DominateBB->getTerminator()))
         continue;
 
       // We only replace the undef when DominateBB truly dominates all the
@@ -171,9 +171,10 @@ bool rewritePHIs(Function &F, LegacyDivergenceAnalysis *DA, DominatorTree *DT) {
 }
 
 bool AMDGPURewriteUndefForPHI::runOnFunction(Function &F) {
-  LegacyDivergenceAnalysis *DA = &getAnalysis<LegacyDivergenceAnalysis>();
+  UniformityInfo &UA =
+      getAnalysis<UniformityInfoWrapperPass>().getUniformityInfo();
   DominatorTree *DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
-  return rewritePHIs(F, DA, DT);
+  return rewritePHIs(F, UA, DT);
 }
 
 FunctionPass *llvm::createAMDGPURewriteUndefForPHIPass() {

llvm/test/CodeGen/AMDGPU/llc-pipeline.ll

@@ -87,8 +87,8 @@
 ; GCN-O0-NEXT:        AMDGPU Annotate Uniform Values
 ; GCN-O0-NEXT:        Natural Loop Information
 ; GCN-O0-NEXT:        SI annotate control flow
-; GCN-O0-NEXT:        Post-Dominator Tree Construction
-; GCN-O0-NEXT:        Legacy Divergence Analysis
+; GCN-O0-NEXT:        Cycle Info Analysis
+; GCN-O0-NEXT:        Uniformity Analysis
 ; GCN-O0-NEXT:        AMDGPU Rewrite Undef for PHI
 ; GCN-O0-NEXT:        LCSSA Verifier
 ; GCN-O0-NEXT:        Loop-Closed SSA Form Pass
@@ -282,8 +282,8 @@
 ; GCN-O1-NEXT:        AMDGPU Annotate Uniform Values
 ; GCN-O1-NEXT:        Natural Loop Information
 ; GCN-O1-NEXT:        SI annotate control flow
-; GCN-O1-NEXT:        Post-Dominator Tree Construction
-; GCN-O1-NEXT:        Legacy Divergence Analysis
+; GCN-O1-NEXT:        Cycle Info Analysis
+; GCN-O1-NEXT:        Uniformity Analysis
 ; GCN-O1-NEXT:        AMDGPU Rewrite Undef for PHI
 ; GCN-O1-NEXT:        LCSSA Verifier
 ; GCN-O1-NEXT:        Loop-Closed SSA Form Pass
@@ -581,8 +581,8 @@
 ; GCN-O1-OPTS-NEXT:        AMDGPU Annotate Uniform Values
 ; GCN-O1-OPTS-NEXT:        Natural Loop Information
 ; GCN-O1-OPTS-NEXT:        SI annotate control flow
-; GCN-O1-OPTS-NEXT:        Post-Dominator Tree Construction
-; GCN-O1-OPTS-NEXT:        Legacy Divergence Analysis
+; GCN-O1-OPTS-NEXT:        Cycle Info Analysis
+; GCN-O1-OPTS-NEXT:        Uniformity Analysis
 ; GCN-O1-OPTS-NEXT:        AMDGPU Rewrite Undef for PHI
 ; GCN-O1-OPTS-NEXT:        LCSSA Verifier
 ; GCN-O1-OPTS-NEXT:        Loop-Closed SSA Form Pass
@@ -888,8 +888,8 @@
 ; GCN-O2-NEXT:        AMDGPU Annotate Uniform Values
 ; GCN-O2-NEXT:        Natural Loop Information
 ; GCN-O2-NEXT:        SI annotate control flow
-; GCN-O2-NEXT:        Post-Dominator Tree Construction
-; GCN-O2-NEXT:        Legacy Divergence Analysis
+; GCN-O2-NEXT:        Cycle Info Analysis
+; GCN-O2-NEXT:        Uniformity Analysis
 ; GCN-O2-NEXT:        AMDGPU Rewrite Undef for PHI
 ; GCN-O2-NEXT:        LCSSA Verifier
 ; GCN-O2-NEXT:        Loop-Closed SSA Form Pass
@@ -1208,8 +1208,8 @@
 ; GCN-O3-NEXT:        AMDGPU Annotate Uniform Values
 ; GCN-O3-NEXT:        Natural Loop Information
 ; GCN-O3-NEXT:        SI annotate control flow
-; GCN-O3-NEXT:        Post-Dominator Tree Construction
-; GCN-O3-NEXT:        Legacy Divergence Analysis
+; GCN-O3-NEXT:        Cycle Info Analysis
+; GCN-O3-NEXT:        Uniformity Analysis
 ; GCN-O3-NEXT:        AMDGPU Rewrite Undef for PHI
 ; GCN-O3-NEXT:        LCSSA Verifier
 ; GCN-O3-NEXT:        Loop-Closed SSA Form Pass