https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89028
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target| |x86_64-*-* i?86-*-*
Status|UNCONFIRMED |NEW
Last reconfirmed| |2019-01-24
Blocks| |53947
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Of course we do not vectorize at -O2. At -O3 the issue is the target doesn't
advertise word_mode as vector size to use and the vectorizer doesn't support
vectorization using half of a vector.
If you'd do
Index: gcc/config/i386/i386.c
===================================================================
--- gcc/config/i386/i386.c (revision 268010)
+++ gcc/config/i386/i386.c (working copy)
@@ -50153,6 +50153,11 @@ ix86_autovectorize_vector_sizes (vector_
sizes->safe_push (32);
sizes->safe_push (16);
}
+ else
+ {
+ sizes->safe_push (16);
+ sizes->safe_push (8);
+ }
}
/* Implemenation of targetm.vectorize.get_mask_mode. */
you get vectorization using DImode regs:
rsqrt:
.LFB0:
.cfi_startproc
movabsq $9187201950435737471, %rdx
movq (%rdi), %rax
movq (%rsi), %rsi
movq %rdx, %rcx
andq %rax, %rcx
andq %rsi, %rdx
xorq %rsi, %rax
addq %rcx, %rdx
movabsq $-9187201950435737472, %rcx
andq %rcx, %rax
xorq %rdx, %rax
movq %rax, (%rdi)
ret
not exactly what you wanted I guess ;) Anything else would require
vectorizer adjustments.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947
[Bug 53947] [meta-bug] vectorizer missed-optimizations
