[PATCH] D123298: [NFC] [AST] Reduce the size of TemplateParmPosition

Chuanqi Xu via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Thu Apr 7 03:58:12 PDT 2022


ChuanqiXu created this revision.
ChuanqiXu added reviewers: erichkeane, aaron.ballman, cor3ntin.
ChuanqiXu added a project: clang.
Herald added a subscriber: kristof.beyls.
Herald added a project: All.
ChuanqiXu requested review of this revision.
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I found this when reading the codes. I think it makes sense to reduce the space for TemplateParmPosition. It is hard to image the depth of template parameter is larger than 2^20 and the index is larger than 2^12. So I think the patch might be reasonable.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D123298

Files:
  clang/include/clang/AST/DeclTemplate.h


Index: clang/include/clang/AST/DeclTemplate.h
===================================================================
--- clang/include/clang/AST/DeclTemplate.h
+++ clang/include/clang/AST/DeclTemplate.h
@@ -1148,10 +1148,8 @@
 /// parameters and is not part of the Decl hierarchy. Just a facility.
 class TemplateParmPosition {
 protected:
-  // FIXME: These probably don't need to be ints. int:5 for depth, int:8 for
-  // position? Maybe?
-  unsigned Depth;
-  unsigned Position;
+  unsigned Depth : 20;
+  unsigned Position : 12;
 
   TemplateParmPosition(unsigned D, unsigned P) : Depth(D), Position(P) {}
 


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