From: Nathan Sidwell <nathan@acm.org>
Date: Wed, 22 Jul 2020 15:07:25 +0000 (-0700)
Subject: c++: Shrink lambda-expr
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=63fa0927e8aba59b1a301f7d13f5cd0e6bb62a66;p=gcc.git

c++: Shrink lambda-expr

I noticed the default capture mode and the discriminator both used
ints.  That seems excessive.  This shrinks them to 8 bits and 16 bits
respectively.  I suppose the discriminator could use the remaining 24
bits of an int allocation unit, if we're worried about more that 64K
lambdas per function.  I know, users are strange :)  On a 64 bit system
this saves 64 bits, because we also had 32 bits of padding added.

	gcc/cp/
	* cp-tree.h (struct tree_lambda_expr): Shrink
	default_capture_mode & discriminator.
---

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index a599f3bad1c..d43c53ae29a 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -1442,8 +1442,8 @@ struct GTY (()) tree_lambda_expr
   tree extra_scope;
   vec<tree, va_gc> *pending_proxies;
   location_t locus;
-  enum cp_lambda_default_capture_mode_type default_capture_mode;
-  int discriminator;
+  enum cp_lambda_default_capture_mode_type default_capture_mode : 8;
+  short int discriminator;
 };
 
 /* Non-zero if this template specialization has access violations that