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From: "ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/109764] V2SI multiply high is not vectorized on x86_64
Date: Mon, 08 May 2023 08:09:46 +0000 [thread overview]
Message-ID: <bug-109764-4-JrbEX7Tc8j@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-109764-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109764
--- Comment #3 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Richard Biener from comment #2)
> Confirmed. Pattern recog recognizes the widening multiplication but not a
> highpart multiplication. That's currently missing.
Please note that the following testcase that multiplies short -> int:
--cut here--
#define N 2
unsigned short ur[N], ua[N], ub[N];
void mulh (void)
{
int i;
for (i = 0; i < N; i++)
ur[i] = ((unsigned int) ua[i] * ub[i]) >> 16;
}
void mulh_slp (void)
{
ur[0] = ((unsigned int) ua[0] * ub[0]) >> 16;
ur[1] = ((unsigned int) ua[1] * ub[1]) >> 16;
}
--cut here--
vectorizes with -O2 -fno-vec-cost-model via .MULH:
vect__15.6_1 = MEM <vector(2) short unsigned int> [(short unsigned int
*)&ua];
vect__17.9_3 = MEM <vector(2) short unsigned int> [(short unsigned int
*)&ub];
vect_patt_34.10_5 = .MULH (vect__15.6_1, vect__17.9_3);
MEM <vector(2) short unsigned int> [(short unsigned int *)&ur] =
vect_patt_34.10_5;
and generates expected:
movd ua(%rip), %xmm0
movd ub(%rip), %xmm1
pmulhuw %xmm1, %xmm0
movd %xmm0, ur(%rip)
in both cases.
prev parent reply other threads:[~2023-05-08 8:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-07 16:21 [Bug tree-optimization/109764] New: " ubizjak at gmail dot com
2023-05-07 16:23 ` [Bug tree-optimization/109764] " ubizjak at gmail dot com
2023-05-08 7:19 ` rguenth at gcc dot gnu.org
2023-05-08 8:09 ` ubizjak at gmail dot com [this message]
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