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.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
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.
---
gcc/testsuite/gcc.dg/vect/pr111764.c | 16 ++++++++++++++++
gcc/tree-vect-loop.cc | 15 +++------------
2 files changed, 19 insertions(+), 12 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/vect/pr111764.c
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 23c6e8259e7..82b793db74b 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -3986,24 +3986,15 @@ 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;
--
2.35.3
