[PATCH] D129683: [Sema] Move Diags.isIgnored() checks off hot paths, it's not free. NFC

[Sam McCall via Phabricator via cfe-commits]

sammccall created this revision.
sammccall added a reviewer: kadircet.
Herald added a subscriber: usaxena95.
Herald added a project: All.
sammccall requested review of this revision.
Herald added subscribers: cfe-commits, ilya-biryukov.
Herald added a project: clang.

This speeds up clangd's buildAST() (i.e. parsing with a preamble) by 5% on
clangd/AST.cpp, by avoiding filling up the diagnostic state map with entries for
all the files where templates are being instantiated from.

(I would assume it has a similar effect on PCH and modules compiles).

This approach is obviously pretty fragile, and we should find ways to make
isIgnored() cheaper instead. But these changes in particular don't seem to make
the code worse in any case.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D129683

Files:
  clang/lib/Sema/Sema.cpp


Index: clang/lib/Sema/Sema.cpp
===================================================================
--- clang/lib/Sema/Sema.cpp
+++ clang/lib/Sema/Sema.cpp
@@ -582,9 +582,6 @@
 }
 
 void Sema::diagnoseZeroToNullptrConversion(CastKind Kind, const Expr* E) {
-  if (Diags.isIgnored(diag::warn_zero_as_null_pointer_constant,
-                      E->getBeginLoc()))
-    return;
   // nullptr only exists from C++11 on, so don't warn on its absence earlier.
   if (!getLangOpts().CPlusPlus11)
     return;
@@ -594,6 +591,10 @@
   if (E->IgnoreParenImpCasts()->getType()->isNullPtrType())
     return;
 
+  if (Diags.isIgnored(diag::warn_zero_as_null_pointer_constant,
+                      E->getBeginLoc()))
+    return;
+
   // Don't diagnose the conversion from a 0 literal to a null pointer argument
   // in a synthesized call to operator<=>.
   if (!CodeSynthesisContexts.empty() &&


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D129683.444375.patch
Type: text/x-patch
Size: 887 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20220713/92851784/attachment.bin>