r237822 - in /trunk/gcc: ChangeLog tree-ssa-mat...

[wilco@gcc.gnu.org]

Author: wilco
Date: Tue Jun 28 13:57:47 2016
New Revision: 237822

URL: https://gcc.gnu.org/viewcvs?rev=237822&root=gcc&view=rev
Log:
This patch fixes a bug in the bswap pass.  In big-endian BIT_FIELD_REF uses
big-endian bit numbering so we need to adjust the bit position.
The existing version could potentially generate incorrect code however GCC
doesn't emit a BIT_FIELD_REF to access the low byte in a register, so the
symbolic number never matches in big-endian.

    gcc/
	* tree-ssa-math-opts.c (find_bswap_or_nop_1): Adjust bitnumbering
	for big-endian BIT_FIELD_REF.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-ssa-math-opts.c