On Mon, Mar 03, 2025 at 12:20:00PM +0000, Richard Sandiford wrote:
> I think we should instead go back to punting on comparisons whose inputs
> are CC modes, as we did (indirectly, via comparison_code_valid_for_mode)
> before r15-6777. Sorry, I'd forgotten/hadn't thought to exclude CC modes
> explicitly when removing that function.
I believe that is not what was the case before r15-6777.
We punted simply because comparison_to_mask returned for GE 6, for LT it
returned 8, 6 | 8 is not 15, no optimization.
There wasn't this all = 14 vs. 15 thing.
comparison_code_valid_for_mode is actually checking mode which is the mode
in which IOR is performed, e.g. SImode in the testcase.
So, do you want a simpler
if (GET_MODE (XEXP (op0, 0)) == MODE_CC
|| HONOR_NANS (GET_MODE (XEXP (op0, 0))))
all = 15;
or
if ((!INTEGRAL_MODE_P (GET_MODE (XEXP (op0, 0)))
&& !FLOAT_MODE_P (GET_MODE (XEXP (op0, 0)))
&& !VECTOR_MODE_P (GET_MODE (XEXP (op0, 0))))
|| HONOR_NANS (GET_MODE (XEXP (op0, 0))))
all = 15;
or something else?
Jakub
