[llvm-branch-commits] [clang] [release/22.x][clang] Avoid calling isInSystemMacro() too often (#182… (PR #182726)

[Timm Baeder via llvm-branch-commits]

https://github.com/tbaederr created https://github.com/llvm/llvm-project/pull/182726

…217)

This caused a performance regression as reported in https://github.com/llvm/llvm-project/pull/141950

>From 8a5b01fbf333806336ba201596f3884c5d8e25db Mon Sep 17 00:00:00 2001
From: Timm Baeder <tbaeder at redhat.com>
Date: Sun, 22 Feb 2026 06:21:33 +0100
Subject: [PATCH] [release/22.x][clang] Avoid calling isInSystemMacro() too
 often (#182217)

This caused a performance regression as reported in
https://github.com/llvm/llvm-project/pull/141950
---
 clang/lib/Basic/DiagnosticIDs.cpp | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/clang/lib/Basic/DiagnosticIDs.cpp b/clang/lib/Basic/DiagnosticIDs.cpp
index a1d9d0f34d20d..45aa901da307c 100644
--- a/clang/lib/Basic/DiagnosticIDs.cpp
+++ b/clang/lib/Basic/DiagnosticIDs.cpp
@@ -562,14 +562,13 @@ DiagnosticIDs::getDiagnosticSeverity(unsigned DiagID, SourceLocation Loc,
       return diag::Severity::Ignored;
   }
   // We also ignore warnings due to system macros
-  if (State->SuppressSystemWarnings && Loc.isValid() &&
-      SM.isInSystemMacro(Loc)) {
+  if (State->SuppressSystemWarnings && Loc.isValid()) {
 
     bool ShowInSystemMacro = true;
     if (const StaticDiagInfoRec *Rec = GetDiagInfo(DiagID))
       ShowInSystemMacro = Rec->WarnShowInSystemMacro;
 
-    if (!ShowInSystemMacro)
+    if (!ShowInSystemMacro && SM.isInSystemMacro(Loc))
       return diag::Severity::Ignored;
   }
   // Clang-diagnostics pragmas always take precedence over suppression mapping.