https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95704
Andrew Pinski changed:
What|Removed |Added
Severity|normal |enhancement
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95704
--- Comment #6 from Segher Boessenkool ---
13 insns, but the longest chain is 4. As I said, not totally awful, and
much better than the branchy code (which does not predict well, for more
general inputs anyway).
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95704
--- Comment #5 from Jens Seifert ---
Power9 code is branchfree but not good at all.
_Z3shloy:
.LFB0:
.cfi_startproc
addi 8,5,-64
subfic 6,5,63
srdi 10,3,1
li 7,0
sld 4,4,5
sld 5,3,5
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95704
--- Comment #4 from Segher Boessenkool ---
It no longer generates that rldicl in GCC 9 (or GCC 10).
You do get straight-line code already if you use -mcpu=power9, btw
(isel; and not totally awful code, but it isn't super of course).
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95704
--- Comment #3 from Jens Seifert ---
GCC 8.3 generates:
_Z3shloy:
.LFB0:
.cfi_startproc
addi 9,5,-64
cmpwi 7,9,0
blt 7,.L2
sld 4,3,9
li 3,0
blr
.p2align 4,,15
.L2:
srdi
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95704
Segher Boessenkool changed:
What|Removed |Added
Status|UNCONFIRMED |NEW
Ever confirmed|0
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95704
--- Comment #1 from Jens Seifert ---
Created attachment 48742
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48742=edit
assembly
