The fragile PHI copying logic in the vectorizer got confused by
constants in loop-closed PHI nodes. Fixed like the following.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
>From a965417cbefd54f45ac6f2b6e3d5dc39c307da09 Mon Sep 17 00:00:00 2001
From: Richard Guenther <rguent...@suse.de>
Date: Mon, 5 Nov 2018 13:02:48 +0100
Subject: [PATCH] fix-pr87873
2018-11-05 Richard Biener <rguent...@suse.de>
PR tree-optimization/87873
* tree-ssa-loop-manip.h (split_loop_exit_edge): Add copy_constants_p
argument.
* tree-ssa-loop-manip.c (split_loop_exit_edge): Likewise.
* tree-vect-loop.c (vect_transform_loop): When splitting the
loop exit also create forwarder PHIs for constants.
* tree-vect-loop-manip.c (slpeel_duplicate_current_defs_from_edges):
Handle constant to_arg, add extra checking we match up the correct
PHIs.
* gcc.dg/pr87873.c: New testcase.
diff --git a/gcc/testsuite/gcc.dg/pr87873.c b/gcc/testsuite/gcc.dg/pr87873.c
new file mode 100644
index 00000000000..63d05342b40
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr87873.c
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O -ftree-loop-vectorize" } */
+
+long k3;
+int gs;
+
+void
+s2 (int aj)
+{
+ while (aj < 1)
+ {
+ gs ^= 1;
+ k3 = (long) gs * 2;
+ if (k3 != 0)
+ k3 = 0;
+
+ ++aj;
+ }
+}
diff --git a/gcc/tree-ssa-loop-manip.c b/gcc/tree-ssa-loop-manip.c
index 5acee6c98f3..726590ac6df 100644
--- a/gcc/tree-ssa-loop-manip.c
+++ b/gcc/tree-ssa-loop-manip.c
@@ -773,10 +773,12 @@ verify_loop_closed_ssa (bool verify_ssa_p, struct loop
*loop)
}
/* Split loop exit edge EXIT. The things are a bit complicated by a need to
- preserve the loop closed ssa form. The newly created block is returned. */
+ preserve the loop closed ssa form. If COPY_CONSTANTS_P is true then
+ forwarder PHIs are also created for constant arguments.
+ The newly created block is returned. */
basic_block
-split_loop_exit_edge (edge exit)
+split_loop_exit_edge (edge exit, bool copy_constants_p)
{
basic_block dest = exit->dest;
basic_block bb = split_edge (exit);
@@ -796,12 +798,13 @@ split_loop_exit_edge (edge exit)
/* If the argument of the PHI node is a constant, we do not need
to keep it inside loop. */
- if (TREE_CODE (name) != SSA_NAME)
+ if (TREE_CODE (name) != SSA_NAME
+ && !copy_constants_p)
continue;
/* Otherwise create an auxiliary phi node that will copy the value
of the SSA name out of the loop. */
- new_name = duplicate_ssa_name (name, NULL);
+ new_name = duplicate_ssa_name (PHI_RESULT (phi), NULL);
new_phi = create_phi_node (new_name, bb);
add_phi_arg (new_phi, name, exit, locus);
SET_USE (op_p, new_name);
diff --git a/gcc/tree-ssa-loop-manip.h b/gcc/tree-ssa-loop-manip.h
index 390ac6f8278..ddda5cf7515 100644
--- a/gcc/tree-ssa-loop-manip.h
+++ b/gcc/tree-ssa-loop-manip.h
@@ -37,7 +37,7 @@ checking_verify_loop_closed_ssa (bool verify_ssa_p, struct
loop *loop = NULL)
verify_loop_closed_ssa (verify_ssa_p, loop);
}
-extern basic_block split_loop_exit_edge (edge);
+extern basic_block split_loop_exit_edge (edge, bool = false);
extern basic_block ip_end_pos (struct loop *);
extern basic_block ip_normal_pos (struct loop *);
extern void standard_iv_increment_position (struct loop *,
diff --git a/gcc/tree-vect-loop-manip.c b/gcc/tree-vect-loop-manip.c
index 1d1d1147696..f1b023b4e4e 100644
--- a/gcc/tree-vect-loop-manip.c
+++ b/gcc/tree-vect-loop-manip.c
@@ -977,10 +977,15 @@ slpeel_duplicate_current_defs_from_edges (edge from, edge
to)
}
if (TREE_CODE (from_arg) != SSA_NAME)
gcc_assert (operand_equal_p (from_arg, to_arg, 0));
- else
+ else if (TREE_CODE (to_arg) == SSA_NAME)
{
if (get_current_def (to_arg) == NULL_TREE)
- set_current_def (to_arg, get_current_def (from_arg));
+ {
+ gcc_assert (types_compatible_p (TREE_TYPE (to_arg),
+ TREE_TYPE (get_current_def
+ (from_arg))));
+ set_current_def (to_arg, get_current_def (from_arg));
+ }
}
gsi_next (&gsi_from);
gsi_next (&gsi_to);
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index 3cdf46d723c..51be405b5a0 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -8236,7 +8236,7 @@ vect_transform_loop (loop_vec_info loop_vinfo)
edge e = single_exit (loop);
if (! single_pred_p (e->dest))
{
- split_loop_exit_edge (e);
+ split_loop_exit_edge (e, true);
if (dump_enabled_p ())
dump_printf (MSG_NOTE, "split exit edge\n");
}
