On Thu, Oct 01, 2026 at 09:43:12AM +0200, Richard Biener wrote:
> works, I wonder why we had the mode check there ... I'm testing this.
When Richard Sandiford introduced it back in 2015, at least for clz/ctz
it was using TYPE_MODE in the C?Z_DEFINED_VALUE_AT_ZERO cases and for the
rest it would be supported for scalar integer modes only anyway.
Now it uses SCALAR_INT_TYPE_MODE in those cases, so will also ICE if it is
not like that, but BITINT_TYPE is an exception:
if (wi::ne_p (arg, 0))
tmp = wi::clz (arg);
else if (BITINT_TYPE_P (arg_type))
tmp = TYPE_PRECISION (arg_type);
else if (!CLZ_DEFINED_VALUE_AT_ZERO (SCALAR_INT_TYPE_MODE (arg_type),
tmp))
tmp = TYPE_PRECISION (arg_type);
Except the
if (SCALAR_INT_MODE_P (mode))
check is not about the argument type (types) but about the result type.
When it was introduced, all the handled functions
(ffs/clz/ctz/clrsb/popcount/parity) had int return type, check for argument
mode would be
if (SCALAR_INT_MODE_P (arg_mode))
in one case and
if (SCALAR_INT_MODE_P (arg0_mode))
in the other case.
I'd say we can just remove the if conditions altogether,
fold_const_call_ss{,s} will just return false for unknown builtins and
for the known ones that it handles all the results are BITINT_TYPE or
SCALAR_INT_MODE_P ones.
Jakub
