public inbox for gcc-cvs@sourceware.org
help / color / mirror / Atom feed
* [gcc r12-10012] tree-optimization/111764 - wrong reduction vectorization
@ 2023-11-27 13:09 Richard Biener
0 siblings, 0 replies; only message in thread
From: Richard Biener @ 2023-11-27 13:09 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:bd75062cc3fc4abd19c37fae164d9764ffab2407
commit r12-10012-gbd75062cc3fc4abd19c37fae164d9764ffab2407
Author: Richard Biener <rguenther@suse.de>
Date: Thu Oct 12 09:09:46 2023 +0200
tree-optimization/111764 - wrong reduction vectorization
The following removes a misguided attempt to allow x + x in a reduction
path, also allowing x * x which isn't valid. x + x actually never
arrives this way but instead is canonicalized to 2 * x. This makes
reduction path handling consistent with how we handle the single-stmt
reduction case.
PR tree-optimization/111764
* tree-vect-loop.cc (check_reduction_path): Remove the attempt
to allow x + x via special-casing of assigns.
* gcc.dg/vect/pr111764.c: New testcase.
(cherry picked from commit 05f98310b54da95e468d799f4a910174320cccbb)
Diff:
---
gcc/testsuite/gcc.dg/vect/pr111764.c | 16 ++++++++++++++++
gcc/tree-vect-loop.cc | 15 +++------------
2 files changed, 19 insertions(+), 12 deletions(-)
diff --git a/gcc/testsuite/gcc.dg/vect/pr111764.c b/gcc/testsuite/gcc.dg/vect/pr111764.c
new file mode 100644
index 00000000000..f4e110f3bbf
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr111764.c
@@ -0,0 +1,16 @@
+#include "tree-vect.h"
+
+short b = 2;
+
+int main()
+{
+ check_vect ();
+
+ for (int a = 1; a <= 9; a++)
+ b = b * b;
+ if (b != 0)
+ __builtin_abort ();
+
+ return 0;
+}
+
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 9df2d5690b7..e1681047d9d 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -3513,24 +3513,15 @@ pop:
??? We could relax this and handle arbitrary live stmts by
forcing a scalar epilogue for example. */
imm_use_iterator imm_iter;
+ use_operand_p use_p;
gimple *op_use_stmt;
unsigned cnt = 0;
FOR_EACH_IMM_USE_STMT (op_use_stmt, imm_iter, op.ops[opi])
if (!is_gimple_debug (op_use_stmt)
&& (*code != ERROR_MARK
|| flow_bb_inside_loop_p (loop, gimple_bb (op_use_stmt))))
- {
- /* We want to allow x + x but not x < 1 ? x : 2. */
- if (is_gimple_assign (op_use_stmt)
- && gimple_assign_rhs_code (op_use_stmt) == COND_EXPR)
- {
- use_operand_p use_p;
- FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter)
- cnt++;
- }
- else
- cnt++;
- }
+ FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter)
+ cnt++;
if (cnt != 1)
{
fail = true;
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2023-11-27 13:09 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-11-27 13:09 [gcc r12-10012] tree-optimization/111764 - wrong reduction vectorization Richard Biener
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).