http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59239
--- Comment #2 from Oleg Endo <olegendo at gcc dot gnu.org> ---
(In reply to Oleg Endo from comment #0)
> Created attachment 31264 [details]
> Possible cleanup patch
After applying the patch and replacing the "doloop_end" expander with
(define_expand "doloop_end"
[(use (match_operand:SI 0 "arith_reg_dest")) ; loop count pseudo
(use (match_operand 1))] ; label
"TARGET_SH2"
{
emit_insn (gen_dect (operands[0], operands[0]));
emit_jump_insn (gen_branch_false (operands[1]));
DONE;
})
will expose the individual decrement-and-test and cbranch insns early. This
shows quite some changes in the CSiBE set. The decrement-and-test insn will be
used less frequently and there are some code size increases with the worst case
being
src/nrrd/convertNrrd 4868 -> 5240 +372 / +7.641742 %
On the other hand, it causes an overall code size decrease of -3944 bytes on
the whole CSiBE set with some of the highlights being
teem-1.6.0-src src/nrrd/tmfKernel 132652 -> 131520 -1132 / -0.853361 %
mpeg2dec-0.3.1 libmpeg2/decode 2820 -> 2620 -200 / -7.092199 %
it looks like fewer registers are used and some loop counter setup calculations
are smaller.
