https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112935
--- Comment #11 from Xi Ruoyao ---
> and tree_nonzero_bits fails to _21 is either 0 or 1, for some reason.
^ report
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112935
--- Comment #10 from Xi Ruoyao ---
For the original test case we get:
x16_27 = _26 & 1;
data_28 = data_15 >> 1;
_29 = crc_18 >> 1;
_21 = (short unsigned int) x16_27;
_13 = _21 * 40961;
and tree_nonzero_bits fails to _21 is either 0
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112935
--- Comment #9 from Xi Ruoyao ---
And in fact the optimal code for
int t(int x, _Bool y)
{
return x * y;
}
should be
maskeqz $r4,$r4,$r5
jr $r1
like
int t(int x, _Bool y)
{
return y ? x : 0;
}
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112935
--- Comment #8 from Xi Ruoyao ---
(In reply to Andrew Pinski from comment #7)
> (In reply to Xi Ruoyao from comment #5)
> >
> > so we still slightly penalty multiplication. To me we should code
> > COSTS_N_INSNS (1) + 1 into
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112935
--- Comment #7 from Andrew Pinski ---
(In reply to Xi Ruoyao from comment #5)
>
> so we still slightly penalty multiplication. To me we should code
> COSTS_N_INSNS (1) + 1 into loongarch_rtx_cost_optimize_size instead of
> special casing it
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112935
--- Comment #6 from Xi Ruoyao ---
On a LA664 it seems a mul.w instruction costs 4 times a "simple" instruction
like add.w/sub.w/and, and div.w costs 5 times.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112935
--- Comment #5 from Xi Ruoyao ---
(In reply to Andrew Pinski from comment #4)
> /* Default RTX cost initializer. */
> ...
> int_mult_si (COSTS_N_INSNS (1)),
> int_mult_di (COSTS_N_INSNS (1)),
>
>
> That seems wrong.
> I suspect you
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112935
--- Comment #4 from Andrew Pinski ---
/* Default RTX cost initializer. */
...
int_mult_si (COSTS_N_INSNS (1)),
int_mult_di (COSTS_N_INSNS (1)),
That seems wrong.
I suspect you will get other improvements when you touch this.
E.g.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112935
Andrew Pinski changed:
What|Removed |Added
Keywords|needs-bisection |missed-optimization
