[llvm] [NVPTX] Avoid repeated map lookups (NFC) (PR #127169)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-nvptx

Author: Kazu Hirata (kazutakahirata)

<details>
<summary>Changes</summary>

Note that cacheAnnotationFromMD modifies AC.Cache.


---
Full diff: https://github.com/llvm/llvm-project/pull/127169.diff


1 Files Affected:

- (modified) llvm/lib/Target/NVPTX/NVPTXUtilities.cpp (+14-8) 


``````````diff
diff --git a/llvm/lib/Target/NVPTX/NVPTXUtilities.cpp b/llvm/lib/Target/NVPTX/NVPTXUtilities.cpp
index 430502d85dfb4..f34d18160b6e0 100644
--- a/llvm/lib/Target/NVPTX/NVPTXUtilities.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXUtilities.cpp
@@ -128,13 +128,16 @@ static std::optional<unsigned> findOneNVVMAnnotation(const GlobalValue *gv,
   auto &AC = getAnnotationCache();
   std::lock_guard<sys::Mutex> Guard(AC.Lock);
   const Module *m = gv->getParent();
-  if (AC.Cache.find(m) == AC.Cache.end())
+  auto ACIt = AC.Cache.find(m);
+  if (ACIt == AC.Cache.end())
     cacheAnnotationFromMD(m, gv);
-  else if (AC.Cache[m].find(gv) == AC.Cache[m].end())
+  else if (ACIt->second.find(gv) == ACIt->second.end())
     cacheAnnotationFromMD(m, gv);
-  if (AC.Cache[m][gv].find(prop) == AC.Cache[m][gv].end())
+  auto &KVP = AC.Cache[m][gv];
+  auto It = KVP.find(prop);
+  if (It == KVP.end())
     return std::nullopt;
-  return AC.Cache[m][gv][prop][0];
+  return It->second[0];
 }
 
 static bool findAllNVVMAnnotation(const GlobalValue *gv,
@@ -143,13 +146,16 @@ static bool findAllNVVMAnnotation(const GlobalValue *gv,
   auto &AC = getAnnotationCache();
   std::lock_guard<sys::Mutex> Guard(AC.Lock);
   const Module *m = gv->getParent();
-  if (AC.Cache.find(m) == AC.Cache.end())
+  auto ACIt = AC.Cache.find(m);
+  if (ACIt == AC.Cache.end())
     cacheAnnotationFromMD(m, gv);
-  else if (AC.Cache[m].find(gv) == AC.Cache[m].end())
+  else if (ACIt->second.find(gv) == ACIt->second.end())
     cacheAnnotationFromMD(m, gv);
-  if (AC.Cache[m][gv].find(prop) == AC.Cache[m][gv].end())
+  auto &KVP = AC.Cache[m][gv];
+  auto It = KVP.find(prop);
+  if (It == KVP.end())
     return false;
-  retval = AC.Cache[m][gv][prop];
+  retval = It->second;
   return true;
 }
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/127169