http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48290
--- Comment #3 from Ira Rosen <irar at il dot ibm.com> 2011-03-28 10:30:55 UTC
---
I am going to test this patch. It checks that if we have a phi in outer loop in
the basic block after the inner loop, then this phi is really inner loop's exit
phi, i.e., its operand is defined in the inner loop.
Index: tree-vect-loop.c
===================================================================
--- tree-vect-loop.c (revision 171466)
+++ tree-vect-loop.c (working copy)
@@ -1184,11 +1184,11 @@ vect_analyze_loop_operations (loop_vec_i
print_gimple_stmt (vect_dump, phi, 0, TDF_SLIM);
}
+ /* Inner-loop loop-closed exit phi in outer-loop vectorization
+ (i.e. a phi in the tail of the outer-loop). */
if (! is_loop_header_bb_p (bb))
{
- /* inner-loop loop-closed exit phi in outer-loop vectorization
- (i.e. a phi in the tail of the outer-loop).
- FORNOW: we currently don't support the case that these phis
+ /* FORNOW: we currently don't support the case that these phis
are not used in the outerloop (unless it is double reduction,
i.e., this phi is vect_reduction_def), cause this case
requires to actually do something here. */
@@ -1202,6 +1202,32 @@ vect_analyze_loop_operations (loop_vec_i
"Unsupported loop-closed phi in outer-loop.");
return false;
}
+
+ /* If PHI is used in the outer loop, we check that its operand
+ is defined in the inner loop. */
+ if (STMT_VINFO_RELEVANT_P (stmt_info))
+ {
+ tree phi_op;
+ gimple op_def_stmt;
+
+ if (gimple_phi_num_args (phi) != 1)
+ return false;
+
+ phi_op = PHI_ARG_DEF (phi, 0);
+ if (TREE_CODE (phi_op) != SSA_NAME)
+ return false;
+
+ op_def_stmt = SSA_NAME_DEF_STMT (phi_op);
+ if (!op_def_stmt || !vinfo_for_stmt (op_def_stmt))
+ return false;
+
+ if (STMT_VINFO_RELEVANT (vinfo_for_stmt (op_def_stmt))
+ != vect_used_in_outer
+ && STMT_VINFO_RELEVANT (vinfo_for_stmt (op_def_stmt))
+ != vect_used_in_outer_by_reduction)
+ return false;
+ }
+
continue;
}
