https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69166
--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
I'm not sure why this check_reduction business exists - but certainly
unconditionally doing
if (code == COND_EXPR)
*v_reduc_type = COND_REDUCTION;
ICEs in the cond-reduction testcases (huh).
So ...
Index: gcc/tree-vect-loop.c
===================================================================
--- gcc/tree-vect-loop.c (revision 232315)
+++ gcc/tree-vect-loop.c (working copy)
@@ -2747,7 +2750,7 @@ vect_is_simple_reduction (loop_vec_info
&& SSA_NAME_DEF_STMT (op1) == phi)
code = PLUS_EXPR;
- if (check_reduction)
+ if (code != COND_EXPR || check_reduction)
{
if (code == COND_EXPR)
*v_reduc_type = COND_REDUCTION;
"works" (testing vect.exp sofar).
So does
Index: gcc/tree-vect-loop.c
===================================================================
--- gcc/tree-vect-loop.c (revision 232315)
+++ gcc/tree-vect-loop.c (working copy)
@@ -2604,10 +2604,12 @@ vect_is_simple_reduction (loop_vec_info
*double_reduc = false;
*v_reduc_type = TREE_CODE_REDUCTION;
+#if 0
/* If CHECK_REDUCTION is true, we assume inner-most loop vectorization,
otherwise, we assume outer loop vectorization. */
gcc_assert ((check_reduction && loop == vect_loop)
|| (!check_reduction && flow_loop_nested_p (vect_loop, loop)));
+#endif
name = PHI_RESULT (phi);
/* ??? If there are no uses of the PHI result the inner loop reduction
@@ -3016,7 +3021,7 @@ vect_force_simple_reduction (loop_vec_in
bool need_wrapping_integral_overflow)
{
enum vect_reduction_type v_reduc_type;
- return vect_is_simple_reduction (loop_info, phi, check_reduction,
+ return vect_is_simple_reduction (loop_info, phi, true,
double_reduc,
need_wrapping_integral_overflow,
&v_reduc_type);
which I believe is "better" (it makes sure we verify the reduction when
initially classifying it as such). That makes outer loop vect / nested cycle
testcases fail though.
Oh well. Need to sit down and understand this stuff some more :/
