https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98697
Bug ID: 98697
Summary: shl not vectorized for v16qi and v8hi with MVE
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: clyon at gcc dot gnu.org
Target Milestone: ---
As described in
https://gcc.gnu.org/pipermail/gcc-patches/2020-December/562235.html we
currently fail to vectorize
dest[i] = a[i] << b[i]
when the element types are v16qi or v8hi
I've committed the support for shl auto-vectorization for MVE in
g:7432f255b70811dafaf325d94036ac580891de69 (r11-6707)
I haven't yet found why the v16qi and v8hi tests are not vectorized.
With dest[i] = a[i] << b[i] and:
{
int i;
unsigned int i.24_1;
unsigned int _2;
int16_t * _3;
short int _4;
int _5;
int16_t * _6;
short int _7;
int _8;
int _9;
int16_t * _10;
short int _11;
unsigned int ivtmp_42;
unsigned int ivtmp_43;
<bb 2> [local count: 119292720]:
<bb 3> [local count: 954449105]:
i.24_1 = (unsigned int) i_23;
_2 = i.24_1 * 2;
_3 = a_15(D) + _2;
_4 = *_3;
_5 = (int) _4;
_6 = b_16(D) + _2;
_7 = *_6;
_8 = (int) _7;
_9 = _5 << _8;
_10 = dest_17(D) + _2;
_11 = (short int) _9;
*_10 = _11;
i_19 = i_23 + 1;
ivtmp_42 = ivtmp_43 - 1;
if (ivtmp_42 != 0)
goto <bb 5>; [87.50%]
else
goto <bb 4>; [12.50%]
<bb 5> [local count: 835156386]:
goto <bb 3>; [100.00%]
<bb 4> [local count: 119292720]:
return;
}
the vectorizer says:
mve-vshl.c:37:96: note: ==> examining statement: _5 = (int) _4;
mve-vshl.c:37:96: note: vect_is_simple_use: operand *_3, type of def:
internal
mve-vshl.c:37:96: note: vect_is_simple_use: vectype vector(8) short int
mve-vshl.c:37:96: missed: conversion not supported by target.
mve-vshl.c:37:96: note: vect_is_simple_use: operand *_3, type of def:
internal
mve-vshl.c:37:96: note: vect_is_simple_use: vectype vector(8) short int
mve-vshl.c:37:96: note: vect_is_simple_use: operand *_3, type of def:
internal
mve-vshl.c:37:96: note: vect_is_simple_use: vectype vector(8) short int
mve-vshl.c:37:117: missed: not vectorized: relevant stmt not supported: _5 =
(int) _4;
mve-vshl.c:37:96: missed: bad operation or unsupported loop bound.
mve-vshl.c:37:96: note: ***** Analysis failed with vector mode V8HI
