On Thu, Mar 21, 2024 at 4:36 PM Takayuki 'January June' Suwa
<jjsuwa_sys3...@yahoo.co.jp> wrote:
>
> int test(int a) {
> return a * 4 + 30000;
> }
>
> In the example above, since Xtensa has instructions to add register value
> scaled by 2, 4 or 8 (and corresponding define_insns), we would expect them
> to be used but not, because it is transformed before reaching the RTL
> generation pass as below:
>
> int test(int a) {
> return (a + 7500) * 4;
> }
>
> Fortunately, the RTL combination pass tries a splitting pattern that matches
> the first example, so it is easy to solve by defining that pattern.
>
> gcc/ChangeLog:
>
> * config/xtensa/xtensa.md: Add new split pattern described above.
> ---
> gcc/config/xtensa/xtensa.md | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
Regtested for target=xtensa-linux-uclibc, no new regressions.
Committed to master.
--
Thanks.
-- Max
