[AMDGPU] Preserve all analyses if nothing changed

[jayfoad]

No description provided.

[llvmbot]

@llvm/pr-subscribers-backend-amdgpu

Author: Jay Foad (jayfoad)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/117994.diff

4 Files Affected:

• (modified) llvm/lib/Target/AMDGPU/AMDGPUAnnotateUniformValues.cpp (+2-2)
• (modified) llvm/lib/Target/AMDGPU/AMDGPUCodeGenPrepare.cpp (+3-1)
• (modified) llvm/lib/Target/AMDGPU/AMDGPULateCodeGenPrepare.cpp (+2-2)
• (modified) llvm/lib/Target/AMDGPU/SIAnnotateControlFlow.cpp (+1-1)

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUAnnotateUniformValues.cpp b/llvm/lib/Target/AMDGPU/AMDGPUAnnotateUniformValues.cpp
index 5feb35a2b553a5..9da0d93341ddfd 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUAnnotateUniformValues.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUAnnotateUniformValues.cpp
@@ -92,10 +92,10 @@ AMDGPUAnnotateUniformValuesPass::run(Function &F,
   AMDGPUAnnotateUniformValues Impl(UI, MSSA, AA, F);
   Impl.visit(F);
 
-  PreservedAnalyses PA = PreservedAnalyses::none();
   if (!Impl.changed())
-    return PA;
+    return PreservedAnalyses::all();
 
+  PreservedAnalyses PA = PreservedAnalyses::none();
   // TODO: Should preserve nearly everything
   PA.preserveSet<CFGAnalyses>();
   return PA;
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUCodeGenPrepare.cpp b/llvm/lib/Target/AMDGPU/AMDGPUCodeGenPrepare.cpp
index c49aab823b44a4..7257b53afe69d0 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUCodeGenPrepare.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUCodeGenPrepare.cpp
@@ -2303,10 +2303,12 @@ PreservedAnalyses AMDGPUCodeGenPreparePass::run(Function &F,
   SIModeRegisterDefaults Mode(F, *Impl.ST);
   Impl.HasFP32DenormalFlush =
       Mode.FP32Denormals == DenormalMode::getPreserveSign();
+  if (!Impl.run(F))
+    return PreservedAnalyses::all();
   PreservedAnalyses PA = PreservedAnalyses::none();
   if (!Impl.FlowChanged)
     PA.preserveSet<CFGAnalyses>();
-  return Impl.run(F) ? PA : PreservedAnalyses::all();
+  return PA;
 }
 
 INITIALIZE_PASS_BEGIN(AMDGPUCodeGenPrepare, DEBUG_TYPE,
diff --git a/llvm/lib/Target/AMDGPU/AMDGPULateCodeGenPrepare.cpp b/llvm/lib/Target/AMDGPU/AMDGPULateCodeGenPrepare.cpp
index 30ef390faab8bd..86ed29acb09abc 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPULateCodeGenPrepare.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPULateCodeGenPrepare.cpp
@@ -484,9 +484,9 @@ AMDGPULateCodeGenPreparePass::run(Function &F, FunctionAnalysisManager &FAM) {
 
   bool Changed = Impl.run(F);
 
-  PreservedAnalyses PA = PreservedAnalyses::none();
   if (!Changed)
-    return PA;
+    return PreservedAnalyses::all();
+  PreservedAnalyses PA = PreservedAnalyses::none();
   PA.preserveSet<CFGAnalyses>();
   return PA;
 }
diff --git a/llvm/lib/Target/AMDGPU/SIAnnotateControlFlow.cpp b/llvm/lib/Target/AMDGPU/SIAnnotateControlFlow.cpp
index ea653490f1bf37..67012669a6df0c 100644
--- a/llvm/lib/Target/AMDGPU/SIAnnotateControlFlow.cpp
+++ b/llvm/lib/Target/AMDGPU/SIAnnotateControlFlow.cpp
@@ -391,7 +391,7 @@ PreservedAnalyses SIAnnotateControlFlowPass::run(Function &F,
   // FIXME: We introduce dead declarations of intrinsics even if never used.
   bool Changed = Impl.run(F);
   if (!Changed)
-    return PreservedAnalyses::none();
+    return PreservedAnalyses::all();
 
   // TODO: Is LoopInfo preserved?
   PreservedAnalyses PA = PreservedAnalyses::none();

[jayfoad]

Found by code inspection.

[jayfoad]

The old code was checking Impl.FlowChanged before calling Impl.run which seems completely wrong.