[llvm] [llvm-profgen] Avoid repeated hash lookups (NFC) (PR #127028)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-pgo

Author: Kazu Hirata (kazutakahirata)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/127028.diff


1 Files Affected:

- (modified) llvm/tools/llvm-profgen/MissingFrameInferrer.cpp (+4-3) 


``````````diff
diff --git a/llvm/tools/llvm-profgen/MissingFrameInferrer.cpp b/llvm/tools/llvm-profgen/MissingFrameInferrer.cpp
index eefe38cd3fa00..ac88fced9159c 100644
--- a/llvm/tools/llvm-profgen/MissingFrameInferrer.cpp
+++ b/llvm/tools/llvm-profgen/MissingFrameInferrer.cpp
@@ -238,12 +238,13 @@ bool MissingFrameInferrer::inferMissingFrames(
     return false;
 
   // Bail out if caller has no known outgoing call edges.
-  if (!CallEdgesF.count(From))
+  auto It = CallEdgesF.find(From);
+  if (It == CallEdgesF.end())
     return false;
 
   // Done with the inference if the calle is reachable via a single callsite.
   // This may not be accurate but it improves the search throughput.
-  if (llvm::is_contained(CallEdgesF[From], ToFRange->Func))
+  if (llvm::is_contained(It->second, ToFRange->Func))
     return true;
 
   // Bail out if callee is not tailcall reachable at all.
@@ -253,7 +254,7 @@ bool MissingFrameInferrer::inferMissingFrames(
   Visiting.clear();
   CurSearchingDepth = 0;
   uint64_t NumPaths = 0;
-  for (auto Target : CallEdgesF[From]) {
+  for (auto Target : It->second) {
     NumPaths +=
         computeUniqueTailCallPath(Target, ToFRange->Func, UniquePath);
     // Stop analyzing the remaining if we are already seeing more than one

``````````

</details>


https://github.com/llvm/llvm-project/pull/127028