On Wed, Jan 12, 2022 at 8:56 PM Kewen.Lin <li...@linux.ibm.com> wrote: > > Hi, > > This patch is to fix register constraint v with > rs6000_constraints[RS6000_CONSTRAINT_v] instead of ALTIVEC_REGS, > just like some other existing register constraints with > RS6000_CONSTRAINT_*. > > I happened to see this and hope it's not intentional and just > got neglected. > > Bootstrapped and regtested on powerpc64le-linux-gnu P9 and > powerpc64-linux-gnu P8. > > Is it ok for trunk?
Why do you want to make this change? rs6000_constraints[RS6000_CONSTRAINT_v] = ALTIVEC_REGS; but all of the patterns that use a "v" constraint are (or should be) protected by TARGET_ALTIVEC, or some final condition that only is active for TARGET_ALTIVEC. The other constraints are conditionally set because they can be used in a pattern with multiple alternatives where the pattern itself is active but some of the constraints correspond to NO_REGS when some instruction variants for VSX is not enabled. The change isn't wrong, but it doesn't correct a bug and provides no additional benefit nor clarty that I can see. Thanks, David
