On Fri, Nov 18, 2016 at 04:43:40PM -0600, Segher Boessenkool wrote: > On Fri, Nov 18, 2016 at 03:38:38PM -0500, Michael Meissner wrote: > > This patch tweaks the movdi constraints for the PowerPC to use "^" or "$" > > constraints instead of "?*". This allows the register allocator to more > > often > > allocate DImode to a floating point/vector register when it is desirable to > > do > > so. > > It also changes some plain "?" to "^" or "$" or even "*" (which cannot > work for multi-character constraints, it skips one character, not one > constraint). Wrong version of the patch?
Note, if '*' does not work with multi-character prefixes, that is a bug. All of rs6000.md assumes that ?*wa means that the register allocator will not consider VSX vector registers for when calculating register preferences. > > I built bootstrap compilers and did make check with no regressions on: > > 1) Little endian power8, --with-cpu=power8 > > 2) Big endian power8, --with-cpu=power8 (no 32-bit support) > > 3) Big endian power7, --with-cpu=power7 (both 32/64-bit support) > > Could you also test with reload please? Just LE is enough I guess. > We'd like to keep reload working for GCC 7 at least, and these cost > prefixes tend to break mov patterns :-/ Argh, I guess you are right, but then if reload doesn't work, I will likely submit the patch where there are three different movdi's (one for 32-bit without the change, one for 64-bit with reload, and one for 64-bit with lra). I would prefer not to do that. -- Michael Meissner, IBM IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA email: meiss...@linux.vnet.ibm.com, phone: +1 (978) 899-4797
