http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44141
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |jakub at gcc dot gnu.org
--- Comment #12 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-03-28
07:47:58 UTC ---
Having a vector mode changing subreg on the LHS of an instruction is a very
common issue in the i386 backend, and unfortunately e.g. means that lots of
insns can't be combined or simplified. I wonder if the expansion sometimes
shouldn't use a non-subregged temporary as lhs and add a move from subreg of
the temporary to the desired destination.
BTW, if with TARGET_SSE_PACKED_SINGLE_INSN_OPTIMAL ps is more desirable than pd
for movs, then perhaps it would be better to add a mode attr similar to
ssemodesuffix, which would emit pd or ps for V2DFmode depending on
TARGET_SSE_PACKED_SINGLE_INSN_OPTIMAL (see e.g. i128 mode attr).
