[llvm] [CodeGen] Avoid repeated hash lookups (NFC) (PR #131495)

[Kazu Hirata via llvm-commits]

https://github.com/kazutakahirata updated https://github.com/llvm/llvm-project/pull/131495

>From c9bb1d8733622156047ed50486036c156b8b3de9 Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sat, 15 Mar 2025 09:15:50 -0700
Subject: [PATCH 1/2] [CodeGen] Avoid repeated hash lookups (NFC)

---
 llvm/lib/CodeGen/MachineDebugify.cpp | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/CodeGen/MachineDebugify.cpp b/llvm/lib/CodeGen/MachineDebugify.cpp
index bffdd51bfbca7..d0e325824c89a 100644
--- a/llvm/lib/CodeGen/MachineDebugify.cpp
+++ b/llvm/lib/CodeGen/MachineDebugify.cpp
@@ -123,10 +123,13 @@ bool applyDebugifyMetadataToMachineFunction(MachineModuleInfo &MMI,
 
       // Find a suitable local variable for the DBG_VALUE.
       unsigned Line = MI.getDebugLoc().getLine();
-      if (!Line2Var.count(Line))
+      auto It = Line2Var.find(Line);
+      if (It == Line2Var.end()) {
         Line = EarliestDVI ? EarliestDVI->getDebugLoc().getLine()
                            : EarliestDVR->getDebugLoc().getLine();
-      DILocalVariable *LocalVar = Line2Var[Line];
+        It = Line2Var.try_emplace(Line).first;
+      }
+      DILocalVariable *LocalVar = It->second;
       assert(LocalVar && "No variable for current line?");
       VarSet.insert(LocalVar);
 

>From f1499ecd68578850b6de59a1084720482207ff1f Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Sun, 16 Mar 2025 10:16:49 -0700
Subject: [PATCH 2/2] Address a comment.

---
 llvm/lib/CodeGen/MachineDebugify.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/CodeGen/MachineDebugify.cpp b/llvm/lib/CodeGen/MachineDebugify.cpp
index d0e325824c89a..9b9cebc74054d 100644
--- a/llvm/lib/CodeGen/MachineDebugify.cpp
+++ b/llvm/lib/CodeGen/MachineDebugify.cpp
@@ -127,7 +127,8 @@ bool applyDebugifyMetadataToMachineFunction(MachineModuleInfo &MMI,
       if (It == Line2Var.end()) {
         Line = EarliestDVI ? EarliestDVI->getDebugLoc().getLine()
                            : EarliestDVR->getDebugLoc().getLine();
-        It = Line2Var.try_emplace(Line).first;
+        It = Line2Var.find(Line);
+        assert(It != Line2Var.end());
       }
       DILocalVariable *LocalVar = It->second;
       assert(LocalVar && "No variable for current line?");