[clang] [clang][Lex][NFC] Reorder SrcMgr checks in CheckMacroName (PR #141483)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Timm Baeder (tbaederr)

<details>
<summary>Changes</summary>

isInPredefinedFile() will look at the presumed loc, which is comparatively slow. Move it after isInSystemFile().

http://llvm-compile-time-tracker.com/compare.php?from=843e362318e884991e517a54446b4faeacdad789&to=de0421a1a38052042721a67a6094f5cb38431f26&stat=instructions:u

---
Full diff: https://github.com/llvm/llvm-project/pull/141483.diff


1 Files Affected:

- (modified) clang/lib/Lex/PPDirectives.cpp (+2-2) 


``````````diff
diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index b2a8459d6b9cc..12688f0939a26 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -373,8 +373,8 @@ bool Preprocessor::CheckMacroName(Token &MacroNameTok, MacroUse isDefineUndef,
   // Macro names with reserved identifiers are accepted if built-in or passed
   // through the command line (the later may be present if -dD was used to
   // generate the preprocessed file).
-  if (!SourceMgr.isInPredefinedFile(MacroNameLoc) &&
-      !SourceMgr.isInSystemHeader(MacroNameLoc)) {
+  if (!SourceMgr.isInSystemHeader(MacroNameLoc) &&
+      !SourceMgr.isInPredefinedFile(MacroNameLoc)) {
     MacroDiag D = MD_NoWarn;
     if (isDefineUndef == MU_Define) {
       D = shouldWarnOnMacroDef(*this, II);

``````````

</details>


https://github.com/llvm/llvm-project/pull/141483