[Bug middle-end/18424] [3.4/4.0 Regression] ~6x+ performance regression, constant trees not being computed.

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

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-12-14 01:47 -------
Subject: Bug 18424

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	gcc-3_4-branch
Changes by:	sayle@gcc.gnu.org	2004-12-14 01:47:35

Modified files:
	gcc            : ChangeLog dojump.c Makefile.in 

Log message:
	PR target/18002
	PR middle-end/18424
	Backport from mainline
	
	2004-03-20  Richard Sandiford  <rsandifo@redhat.com>
	* Makefile.in (dojump.o): Depend on $(GGC_H) and dojump.h.
	(GTFILES): Add $(srcdir)/dojump.h.
	(gt-dojump.h): New dependency.
	* dojump.c (and_reg, and_test, shift_test): New static variables.
	(prefer_and_bit_test): New function.
	(do_jump): Use it to choose between (X & (1 << C)) and (X >> C) & 1.
	
	2004-03-21  Andrew Pinski  <pinskia@gcc.gnu.org>
	* dojump.c (prefer_and_bit_test): Fix which part of
	the and_test is replaced.
	
	2004-12-10  Roger Sayle  <roger@eyesopen.com>
	* dojump.c (do_jump): When attempting to reverse the effects of
	fold_single_bit_test, we need to STRIP_NOPS and narrowing type
	conversions, and handle BIT_XOR_EXPR that's used to invert the
	sense of the single bit test.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=2.2326.2.730&r2=2.2326.2.731
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/dojump.c.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.9.4.1&r2=1.9.4.2
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/Makefile.in.diff?cvsroot=gcc&only_with_tag=gcc-3_4-branch&r1=1.1223.2.20&r2=1.1223.2.21



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18424