[llvm] [NFC][AMDGPU][Attributor] Exit earlier if entry CC (PR #114177)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-amdgpu

Author: Shilei Tian (shiltian)

<details>
<summary>Changes</summary>

Avoid calling TTI or other stuff unnecessarily

---
Full diff: https://github.com/llvm/llvm-project/pull/114177.diff


1 Files Affected:

- (modified) llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp (+12-6) 


``````````diff
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp b/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp
index 6a69b9d2bfc716..04d3e482359ade 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp
@@ -767,14 +767,17 @@ struct AAAMDFlatWorkGroupSize : public AAAMDSizeRangeAttribute {
 
   void initialize(Attributor &A) override {
     Function *F = getAssociatedFunction();
+
+    if (AMDGPU::isEntryFunctionCC(F->getCallingConv())) {
+      indicatePessimisticFixpoint();
+      return;
+    }
+
     auto &InfoCache = static_cast<AMDGPUInformationCache &>(A.getInfoCache());
     unsigned MinGroupSize, MaxGroupSize;
     std::tie(MinGroupSize, MaxGroupSize) = InfoCache.getFlatWorkGroupSizes(*F);
     intersectKnown(
         ConstantRange(APInt(32, MinGroupSize), APInt(32, MaxGroupSize + 1)));
-
-    if (AMDGPU::isEntryFunctionCC(F->getCallingConv()))
-      indicatePessimisticFixpoint();
   }
 
   ChangeStatus updateImpl(Attributor &A) override {
@@ -833,6 +836,12 @@ struct AAAMDWavesPerEU : public AAAMDSizeRangeAttribute {
 
   void initialize(Attributor &A) override {
     Function *F = getAssociatedFunction();
+
+    if (AMDGPU::isEntryFunctionCC(F->getCallingConv())) {
+      indicatePessimisticFixpoint();
+      return;
+    }
+
     auto &InfoCache = static_cast<AMDGPUInformationCache &>(A.getInfoCache());
 
     if (const auto *AssumedGroupSize = A.getAAFor<AAAMDFlatWorkGroupSize>(
@@ -847,9 +856,6 @@ struct AAAMDWavesPerEU : public AAAMDSizeRangeAttribute {
       ConstantRange Range(APInt(32, Min), APInt(32, Max + 1));
       intersectKnown(Range);
     }
-
-    if (AMDGPU::isEntryFunctionCC(F->getCallingConv()))
-      indicatePessimisticFixpoint();
   }
 
   ChangeStatus updateImpl(Attributor &A) override {

``````````

</details>


https://github.com/llvm/llvm-project/pull/114177