[Bug tree-optimization/15310] [tree-ssa] Optimize an addition in a bit field

["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  2004-06-30 10:10 -------
Subject: Bug 15310

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	jakub@gcc.gnu.org	2004-06-30 10:09:55

Modified files:
	gcc            : ChangeLog simplify-rtx.c expr.c 
	gcc/testsuite  : ChangeLog 
Added files:
	gcc/testsuite/gcc.c-torture/execute: 20040629-1.c 

Log message:
	* simplify-rtx.c (simplify_binary_operation): Simplify
	((A & N) + B) & M -> (A + B) & M if M is pow2 minus 1 constant and
	N has at least all bits in M set as well.
	
	PR tree-optimization/15310
	* expr.c (expand_assignment): Optimize += or -= on a bit field in
	most significant bits.
	
	* gcc.c-torture/execute/20040629-1.c: New test.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.4205&r2=2.4206
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/simplify-rtx.c.diff?cvsroot=gcc&r1=1.194&r2=1.195
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/expr.c.diff?cvsroot=gcc&r1=1.657&r2=1.658
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.3919&r2=1.3920
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.c-torture/execute/20040629-1.c.diff?cvsroot=gcc&r1=NONE&r2=1.1



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15310