On Thu, Jan 29, 2026 at 7:23 PM Jeffrey Law <[email protected]> wrote: > > > > 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.
Yes it should be a special case as that is how it is handled in force_operand. I added the note about div to the changelog too. Attached is the full patch which I pushed. Thanks, Andrew Pinski > > jeff
0001-ifcvt-Improve-noce_can_force_operand-in-ifcvt-PR1221.patch
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