r253717 - in /trunk/gcc: ChangeLog combine.c

[rsandifo@gcc.gnu.org]

Author: rsandifo
Date: Fri Oct 13 09:58:23 2017
New Revision: 253717

URL: https://gcc.gnu.org/viewcvs?rev=253717&root=gcc&view=rev
Log:
Prevent invalid register mode changes in combine

This patch stops combine from changing the mode of an existing register
in-place if doing so would change the size of the underlying register
allocation size, as given by REGMODE_NATURAL_SIZE.  Without this,
many tests fail in adjust_reg_mode after SVE is added.  One example
is gcc.c-torture/compile/20090401-1.c.

2017-10-13  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* combine.c (can_change_dest_mode): Reject changes in
	REGMODE_NATURAL_SIZE.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/combine.c