https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113542
Maxim Kuvyrkov <mkuvyrkov at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |mkuvyrkov at gcc dot gnu.org
--- Comment #3 from Maxim Kuvyrkov <mkuvyrkov at gcc dot gnu.org> ---
Copy-pasting my comment from
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111267#c15 :
I've looked into the reason for the above failures, and it seems to be not an
issue.
After the patch fwprop1 decides to do an additional propagation, which was
considered as "would increase complexity of pattern" before the patch. This
results in change from "bics; mov" to "bic; subs". If I understand ARM
assembler correctly, handling of sign was shifted from "bics" to "subs"
instruction.
This is the actual code: BEFORE:
bics r0, r0, r1 @ 9 [c=4 l=4]
*andsi_notsi_si_compare0_scratch
mov r0, #1 @ 23 [c=4 l=4] *thumb2_movsi_vfp/1
it eq
moveq r0, #0 @ 26 [c=8 l=4] *p *thumb2_movsi_vfp/2
bx lr @ 29 [c=8 l=4] *thumb2_return
and AFTER:
bic r0, r0, r1 @ 8 [c=4 l=4] andsi_notsi_si
subs r0, r0, #0 @ 22 [c=4 l=4] cmpsi2_addneg/0
it ne
movne r0, #1 @ 23 [c=8 l=4] *p *thumb2_movsi_vfp/2
bx lr @ 26 [c=8 l=4] *thumb2_return
If I don't hear anything to the contrary, I'll update the testcase to accept
both "bic" and "bics".
