On 1/28/2026 6:01 PM, Andrew Pinski wrote:
Currently if the rtl is either an arithmetic or an unary
rtl, noce_can_force_operand checks to see if there is an
optab for that rtl code. This works for more things except
on some targets they have a ss_minus instruction but don't
implement the optab for it. In the case of arm you can
generate a ss_minus with a builtin and then when it comes
to trying to do ifcvt, force_operand fails over.
In this case the optab, sssub was only supported for
fixed-point modes before and it was working as code_to_optab
would return there was not optabs. But after r15-1030-gabe6d39365476e,
the optab will be return. What the backend is doing is correct and will
most likely happen with other rtl codes/optabs later on.
To fix this instead of just returning true if the optab exists, we need
to check if the optab entry for the mode exists.
PR rtl-optimization/122170
gcc/ChangeLog:
* ifcvt.cc (noce_can_force_operand): Don;t only check if
there is an optab for the code check the entry for the
mode is non-null.
I'm going to assume the special case for DIV is desirable. Nit in the
ChangeLog, replace the semicolon with a single quote.
OK with that change, assuming I'm right about the desire to special case
DIV.
jeff
