On Fri, Jul 15, 2022 at 4:17 PM Takayuki 'January June' Suwa
<jjsuwa_sys3...@yahoo.co.jp> wrote:
>
> This patch allows the constant synthesis to choose shorter instruction
> if possible.
>
> /* example */
> int test(void) {
> return 128 << 8;
> }
>
> ;; before
> test:
> movi a2, 0x100
> addmi a2, a2, 0x7f00
> ret.n
>
> ;; after
> test:
> movi.n a2, 1
> slli a2, a2, 15
> ret.n
>
> When the Code Density Option is configured, the latter is one byte smaller
> than the former.
>
> gcc/ChangeLog:
>
> * config/xtensa/xtensa.cc (xtensa_emit_constantsynth): Remove.
> (xtensa_constantsynth_2insn): Change to try all three synthetic
> methods and to use the one that fits the immediate value of
> the seed into a Narrow Move Immediate instruction "MOVI.N"
> when the Code Density Option is configured.
> ---
> gcc/config/xtensa/xtensa.cc | 58 ++++++++++++++++++-------------------
> 1 file changed, 29 insertions(+), 29 deletions(-)
Regtested for target=xtensa-linux-uclibc, no new regressions.
Committed to master.
--
Thanks.
-- Max
