We're running into a multiplication with one unvectorizable
operand we expect to build from scalars but SLP discovery
fatally fails the build of both since one stmt is commutated:
_60 = _58 * _59;
_63 = _59 * _62;
_66 = _59 * _65;
...
where _59 is the "bad" operand. The following patch makes the
case work where the first stmt has a good operand by not fatally
failing the SLP build for the operand but communicating upwards
how to commutate.
Bootstrapped / tested on x86_64-unknown-linux-gnu, pushed.
2020-10-09 Richard Biener <rguent...@suse.de>
PR tree-optimization/97334
* tree-vect-slp.c (vect_build_slp_tree_1): Do not fatally
fail lanes other than zero when BB vectorizing.
* gcc.dg/vect/bb-slp-pr65935.c: Amend.
---
gcc/testsuite/gcc.dg/vect/bb-slp-pr65935.c | 3 +++
gcc/tree-vect-slp.c | 22 ++++++++++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/gcc/testsuite/gcc.dg/vect/bb-slp-pr65935.c
b/gcc/testsuite/gcc.dg/vect/bb-slp-pr65935.c
index 4e3448eccd7..ea37e4e614c 100644
--- a/gcc/testsuite/gcc.dg/vect/bb-slp-pr65935.c
+++ b/gcc/testsuite/gcc.dg/vect/bb-slp-pr65935.c
@@ -60,3 +60,6 @@ int main()
/* We should also be able to use 2-lane SLP to initialize the real and
imaginary components in the first loop of main. */
/* { dg-final { scan-tree-dump-times "optimized: basic block" 10 "slp1" } } */
+/* We should see the s->phase[dir] operand and only that operand built
+ from scalars. See PR97334. */
+/* { dg-final { scan-tree-dump-times "Building vector operands from scalars" 1
"slp1" } } */
diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index 479c3eeaec7..495fb970e24 100644
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -773,6 +773,12 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char
*swap,
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
"Build SLP failed: unvectorizable statement %G",
stmt);
+ /* ??? For BB vectorization we want to commutate operands in a way
+ to shuffle all unvectorizable defs into one operand and have
+ the other still vectorized. The following doesn't reliably
+ work for this though but it's the easiest we can do here. */
+ if (is_a <bb_vec_info> (vinfo) && i != 0)
+ continue;
/* Fatal mismatch. */
matches[0] = false;
return false;
@@ -785,6 +791,8 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
"Build SLP failed: not GIMPLE_ASSIGN nor "
"GIMPLE_CALL %G", stmt);
+ if (is_a <bb_vec_info> (vinfo) && i != 0)
+ continue;
/* Fatal mismatch. */
matches[0] = false;
return false;
@@ -797,6 +805,8 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
&& !vect_record_max_nunits (vinfo, stmt_info, group_size,
nunits_vectype, max_nunits)))
{
+ if (is_a <bb_vec_info> (vinfo) && i != 0)
+ continue;
/* Fatal mismatch. */
matches[0] = false;
return false;
@@ -823,6 +833,8 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
"Build SLP failed: unsupported call type %G",
call_stmt);
+ if (is_a <bb_vec_info> (vinfo) && i != 0)
+ continue;
/* Fatal mismatch. */
matches[0] = false;
return false;
@@ -865,6 +877,8 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
"Build SLP failed: no optab.\n");
+ if (is_a <bb_vec_info> (vinfo) && i != 0)
+ continue;
/* Fatal mismatch. */
matches[0] = false;
return false;
@@ -876,6 +890,8 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
"Build SLP failed: "
"op not supported by target.\n");
+ if (is_a <bb_vec_info> (vinfo) && i != 0)
+ continue;
/* Fatal mismatch. */
matches[0] = false;
return false;
@@ -900,6 +916,8 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
if (TREE_CODE (vec) != SSA_NAME
|| !types_compatible_p (vectype, TREE_TYPE (vec)))
{
+ if (is_a <bb_vec_info> (vinfo) && i != 0)
+ continue;
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
"Build SLP failed: "
@@ -1048,6 +1066,8 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char
*swap,
"Build SLP failed: not grouped load %G", stmt);
/* FORNOW: Not grouped loads are not supported. */
+ if (is_a <bb_vec_info> (vinfo) && i != 0)
+ continue;
/* Fatal mismatch. */
matches[0] = false;
return false;
@@ -1066,6 +1086,8 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char
*swap,
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
"Build SLP failed: operation unsupported %G",
stmt);
+ if (is_a <bb_vec_info> (vinfo) && i != 0)
+ continue;
/* Fatal mismatch. */
matches[0] = false;
return false;
--
2.26.2
