On 4/13/22 14:57, Richard Biener via Gcc-patches wrote:
When doing BB vectorization the scalar cost compute is derailed
by patterns, causing lanes to be considered live and thus not
costed on the scalar side. For the testcase in PR104010 this
prevents vectorization which was done by GCC 11. PR103941
shows similar cases of missed optimizations that are fixed by
this patch.
Bootstrapped and tested on x86_64-unknown-linux-gnu.
I'm only considering this now because PR104010 is identified
as regression on arm - Richards, what do you think? I do think
this will enable vectorization of more stuff now which might
be good or bad - who knowns, but at least it needs to involve
patterns.
Thanks,
Richard.
2022-04-13 Richard Biener <rguent...@suse.de>
PR tree-optimization/104010
PR tree-optimization/103941
* tree-vect-slp.cc (vect_bb_slp_scalar_cost): When
we run into stmts in patterns continue walking those
for uses outside of the vectorized region instead of
marking the lane live.
Thanks!
I do confirm that without your patch gcc.target/arm/simd/neon-vcmp.c
fails, and passes with your patch. Sorry for the delay.
Christophe
* gcc.target/i386/pr103941-1.c: New testcase.
* gcc.target/i386/pr103941-2.c: Likewise.
---
gcc/testsuite/gcc.target/i386/pr103941-1.c | 14 +++++++
gcc/testsuite/gcc.target/i386/pr103941-2.c | 12 ++++++
gcc/tree-vect-slp.cc | 47 ++++++++++++++++------
3 files changed, 61 insertions(+), 12 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/pr103941-1.c
create mode 100644 gcc/testsuite/gcc.target/i386/pr103941-2.c
diff --git a/gcc/testsuite/gcc.target/i386/pr103941-1.c
b/gcc/testsuite/gcc.target/i386/pr103941-1.c
new file mode 100644
index 00000000000..524fdd0b4b1
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr103941-1.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -msse2" } */
+
+unsigned char ur[16], ua[16], ub[16];
+
+void avgu_v2qi (void)
+{
+ int i;
+
+ for (i = 0; i < 2; i++)
+ ur[i] = (ua[i] + ub[i] + 1) >> 1;
+}
+
+/* { dg-final { scan-assembler "pavgb" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr103941-2.c
b/gcc/testsuite/gcc.target/i386/pr103941-2.c
new file mode 100644
index 00000000000..972a32be997
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr103941-2.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -msse2" } */
+
+void foo (int *c, float *x, float *y)
+{
+ c[0] = x[0] < y[0];
+ c[1] = x[1] < y[1];
+ c[2] = x[2] < y[2];
+ c[3] = x[3] < y[3];
+}
+
+/* { dg-final { scan-assembler "cmpltps" } } */
diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 4ac2b70303c..c7687065374 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -5185,22 +5185,45 @@ vect_bb_slp_scalar_cost (vec_info *vinfo,
the scalar cost. */
if (!STMT_VINFO_LIVE_P (stmt_info))
{
- FOR_EACH_PHI_OR_STMT_DEF (def_p, orig_stmt, op_iter, SSA_OP_DEF)
+ auto_vec<gimple *, 8> worklist;
+ hash_set<gimple *> *worklist_visited = NULL;
+ worklist.quick_push (orig_stmt);
+ do
{
- imm_use_iterator use_iter;
- gimple *use_stmt;
- FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, DEF_FROM_PTR (def_p))
- if (!is_gimple_debug (use_stmt))
- {
- stmt_vec_info use_stmt_info = vinfo->lookup_stmt (use_stmt);
- if (!use_stmt_info
- || !vectorized_scalar_stmts.contains (use_stmt_info))
+ gimple *work_stmt = worklist.pop ();
+ FOR_EACH_PHI_OR_STMT_DEF (def_p, work_stmt, op_iter, SSA_OP_DEF)
+ {
+ imm_use_iterator use_iter;
+ gimple *use_stmt;
+ FOR_EACH_IMM_USE_STMT (use_stmt, use_iter,
+ DEF_FROM_PTR (def_p))
+ if (!is_gimple_debug (use_stmt))
{
- (*life)[i] = true;
- break;
+ stmt_vec_info use_stmt_info
+ = vinfo->lookup_stmt (use_stmt);
+ if (!use_stmt_info
+ || !vectorized_scalar_stmts.contains
(use_stmt_info))
+ {
+ if (STMT_VINFO_IN_PATTERN_P (use_stmt_info))
+ {
+ /* For stmts participating in patterns we have
+ to check its uses recursively. */
+ if (!worklist_visited)
+ worklist_visited = new hash_set<gimple *> ();
+ if (!worklist_visited->add (use_stmt))
+ worklist.safe_push (use_stmt);
+ continue;
+ }
+ (*life)[i] = true;
+ goto next_lane;
+ }
}
- }
+ }
}
+ while (!worklist.is_empty ());
+next_lane:
+ if (worklist_visited)
+ delete worklist_visited;
if ((*life)[i])
continue;
}
