r196451 - in /trunk/gcc: ChangeLog simplify-rtx...

[jakub@gcc.gnu.org]

Author: jakub
Date: Tue Mar  5 06:04:14 2013
New Revision: 196451

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=196451
Log:
	PR rtl-optimization/56494
	* simplify-rtx.c (simplify_truncation): If C is narrower than A,
	optimize (truncate:A (subreg:B (truncate:C X) 0)) into
	(subreg:A (truncate:C X) 0) instead of (truncate:A X).

	* gcc.dg/pr56494.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/pr56494.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/simplify-rtx.c
    trunk/gcc/testsuite/ChangeLog