On 11/07/14 08:58, Thomas Preud'homme wrote:
Trunk revision 216971 introduced LROTATE_EXPR as the canonical representation
for a byte swap of a 2 bytes value, as per [1]. However, backend expects
bswaphi patterns for such operation as these operation are more specific than a
rotation. This led to a number of testcases starting to fail such as
gcc.target/arm/builtin-bswap16-1.c and gcc.target/aarch64/builtin-bswap-2.c
(these were skipped with my configuration). This patch adds a check in expmed
to expand such LROTATE_EXPR into bswaphi pattern.
[1] https://gcc.gnu.org/ml/gcc-patches/2014-10/msg00616.html
Note that this is unrelated to PR63761 (but I have diagnosed the root cause).
ChangeLog entry is as follows:
2014-11-03 Thomas Preud'homme <thomas.preudho...@arm.com>
* expmed.c (expand_shift_1): Expand 8 bit rotate of 16 bit value to
bswaphi if available.
Why restrict this to 8 bit rotate of a 16 bit value? Shouldn't it apply
to a 16 bit rotate of a 32 bit value, or 32 bit rotate of 64 bit value?
Jeff
