[Bug tree-optimization/23109] [4.1 Regression] compiler generates wrong code leading to spurious division by zero with -funsafe-math-optimizations (instead of -ftrapping-math)

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-08-01 08:53 -------
Subject: Bug 23109

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	rguenth@gcc.gnu.org	2005-08-01 08:53:00

Modified files:
	gcc            : ChangeLog tree-ssa-loop-im.c 
	                 tree-ssa-math-opts.c 

Log message:
	2005-08-01  Richard Guenther  <rguenther@suse.de>
	
	PR tree-optimization/23109
	* tree-ssa-math-opts.c (execute_cse_reciprocals_1):
	If trapping math is in effect, use post-dominator information
	to check if we'd in any case reach a trapping point before
	doing the reciprocal insertion.
	(execute_cse_reciprocals): Compute post-dominators, if necessary.
	* tree-ssa-loop-im.c (determine_invariantness_stmt): RDIV
	expressions are invariant only if trapping math is not in effect.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.9622&r2=2.9623
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-ssa-loop-im.c.diff?cvsroot=gcc&r1=2.48&r2=2.49
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-ssa-math-opts.c.diff?cvsroot=gcc&r1=2.2&r2=2.3



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23109