public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug c/113666] New: RISC-V: Cost model test regression due to recent middle-end loop vectorizer changes
@ 2024-01-30 2:08 juzhe.zhong at rivai dot ai
0 siblings, 0 replies; only message in thread
From: juzhe.zhong at rivai dot ai @ 2024-01-30 2:08 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113666
Bug ID: 113666
Summary: RISC-V: Cost model test regression due to recent
middle-end loop vectorizer changes
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: juzhe.zhong at rivai dot ai
Target Milestone: ---
FAIL: gcc.dg/vect/costmodel/riscv/rvv/pr113281-1.c scan-assembler-not vset
FAIL: gcc.dg/vect/costmodel/riscv/rvv/pr113281-2.c scan-assembler-not vset
FAIL: gcc.dg/vect/costmodel/riscv/rvv/pr113281-5.c scan-assembler-not vset
unsigned char a;
int main() {
short b = a = 0;
for (; a != 19; a++)
if (a)
b = 32872 >> a;
if (b == 0)
return 0;
else
return 1;
}
-march=rv64gcv_zvl256b -mabi=lp64d -O3 -ftree-vectorize
We expect:
lui a5,%hi(a)
li a4,19
sb a4,%lo(a)(a5)
li a0,0
ret
However, we now have:
vsetvli a5,zero,e8,mf4,ta,ma
li a6,17
li a3,32768
vid.v v2
addiw a3,a3,104
vadd.vx v2,v2,a6
lui a1,%hi(a)
vsetvli zero,zero,e32,m1,ta,ma
li a0,19
vmv.v.x v1,a3
vzext.vf4 v3,v2
sb a0,%lo(a)(a1)
vsra.vv v1,v1,v3
vsetvli zero,zero,e16,mf2,ta,ma
vncvt.x.x.w v1,v1
vslidedown.vi v1,v1,1
vmv.x.s a0,v1
snez a0,a0
ret
I guess it is caused by this commit:
https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=1a8261e047f7a2c2b0afb95716f7615cba718cd1
I don't known how to fix RISC-V backend cost model to recover back since
current
cost scalar_to_vec seems is already very high, it makes no sense to keep
raising
the cost of it.
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2024-01-30 2:08 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-01-30 2:08 [Bug c/113666] New: RISC-V: Cost model test regression due to recent middle-end loop vectorizer changes juzhe.zhong at rivai dot ai
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).