[gcc/devel/autopar_devel] tree-optimization/95916 - treat scalar ops explicitely

[Giuliano Belinassi]

https://gcc.gnu.org/g:3b34bf874b919b222bd4a326fe01001718b6e29d

commit 3b34bf874b919b222bd4a326fe01001718b6e29d
Author: Richard Biener <rguenther@suse.de>
Date:   Mon Jun 29 13:53:51 2020 +0200

    tree-optimization/95916 - treat scalar ops explicitely
    
    This explicitely treats the case of scalar operands for SLP
    when computing insert locations.
    
    2020-06-29  Richard Biener  <rguenther@suse.de>
    
            PR tree-optimization/95916
            * tree-vect-slp.c (vect_schedule_slp_instance): Explicitely handle
            the case of not vectorized externals.
    
            * gcc.dg/vect/pr95916.c: New testcase.

Diff:
---
 gcc/testsuite/gcc.dg/vect/pr95916.c | 13 +++++++++++++
 gcc/tree-vect-slp.c                 | 15 +++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/gcc/testsuite/gcc.dg/vect/pr95916.c b/gcc/testsuite/gcc.dg/vect/pr95916.c
new file mode 100644
index 00000000000..61b8ca3fa0c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr95916.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-O3" } */
+
+extern short var_3, var_8;
+extern int var_5;
+extern char var_10;
+extern int arr_99[][16];
+void test()
+{
+  for (; 0 < var_10;)
+    for (long a = var_8;; a++)
+      arr_99[4][a] = var_3 << var_5;
+}
diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index b223956e3af..1ffbf6f6af9 100644
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -4293,6 +4293,21 @@ vect_schedule_slp_instance (vec_info *vinfo,
 		  || vect_stmt_dominates_stmt_p (last_stmt, vstmt))
 		last_stmt = vstmt;
 	  }
+	else if (!SLP_TREE_VECTYPE (child))
+	  {
+	    /* For externals we use unvectorized at all scalar defs.  */
+	    unsigned j;
+	    tree def;
+	    FOR_EACH_VEC_ELT (SLP_TREE_SCALAR_OPS (child), j, def)
+	      if (TREE_CODE (def) == SSA_NAME
+		  && !SSA_NAME_IS_DEFAULT_DEF (def))
+		{
+		  gimple *stmt = SSA_NAME_DEF_STMT (def);
+		  if (!last_stmt
+		      || vect_stmt_dominates_stmt_p (last_stmt, stmt))
+		    last_stmt = stmt;
+		}
+	  }
 	else
 	  {
 	    /* For externals we have to look at all defs since their