[Bug optimization/8967] [3.4 regression] Making class data members `const' pessimizes code

["cvs-commit at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=8967



------- Additional Comments From cvs-commit at gcc dot gnu dot org  2003-09-12 15:08 -------
Subject: Bug 8967

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	sayle@gcc.gnu.org	2003-09-12 15:07:52

Modified files:
	gcc            : ChangeLog alias.c rtl.h flow.c 

Log message:
	PR optimization/8967
	* alias.c (write_dependence_p): Modify to take an additional constp
	argument that controls whether the UNCHANGING_RTX_P flags are used.
	(anti_dependence, output_dependence): Adjust write_dependence_p
	callers to pass this additional argument, to return the same result.
	(unchanging_anti_dependence): New variant of anti_dependence that
	ignores the UNCHANGING_RTX_P property on memory references.
	* rtl.h (unchaning_anti_dependence): Prototype here.
	* flow.c (init_propagate_block): Place fake constant mem writes on
	the mem_set_list so that dead writes to const variables are deleted.
	(insn_dead_p): Change anti_dependence to unchanging_anti_dependence.
	(mark_used_regs): Likewise.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.1036&r2=2.1037
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/alias.c.diff?cvsroot=gcc&r1=1.199&r2=1.200
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/rtl.h.diff?cvsroot=gcc&r1=1.434&r2=1.435
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/flow.c.diff?cvsroot=gcc&r1=1.561&r2=1.562