[gcc r12-9260] tree-optimization/108816 - vect versioning check split confusion

[Richard Biener]

https://gcc.gnu.org/g:02ff8c8ebcb7f9b0885946d17ff12523e7522b71

commit r12-9260-g02ff8c8ebcb7f9b0885946d17ff12523e7522b71
Author: Richard Biener <rguenther@suse.de>
Date:   Mon Feb 20 10:59:15 2023 +0100

    tree-optimization/108816 - vect versioning check split confusion
    
    The split of the versioning condition assumes the definition is
    in the condition block which is ensured by the versioning code.
    But that only works when we actually have to insert any statements
    for the versioning condition.  The following adjusts the guard
    accordingly and asserts this condition.
    
            PR tree-optimization/108816
            * tree-vect-loop-manip.cc (vect_loop_versioning): Adjust
            versioning condition split prerequesite, assert required
            invariant.
    
            * gcc.dg/torture/pr108816.c: New testcase.
    
    (cherry picked from commit 63471c5008819bbf6ec32a6f4d8701fe57b96fa9)

Diff:
---
 gcc/testsuite/gcc.dg/torture/pr108816.c | 18 ++++++++++++++++++
 gcc/tree-vect-loop-manip.cc             |  3 ++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/gcc/testsuite/gcc.dg/torture/pr108816.c b/gcc/testsuite/gcc.dg/torture/pr108816.c
new file mode 100644
index 00000000000..4c24d5584c1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr108816.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-fvect-cost-model=dynamic" } */
+
+int m;
+
+void
+foo (int p[][16], unsigned int x)
+{
+  while (x < 4)
+    {
+      int j;
+
+      for (j = x * 4; j < (x + 1) * 4 - 2; j++)
+        p[0][j] = p[m][j];
+
+      ++x;
+    }
+}
diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
index cb5bb87ae33..9d21e6d0310 100644
--- a/gcc/tree-vect-loop-manip.cc
+++ b/gcc/tree-vect-loop-manip.cc
@@ -3450,7 +3450,7 @@ vect_loop_versioning (loop_vec_info loop_vinfo,
   tree cost_name = NULL_TREE;
   profile_probability prob2 = profile_probability::uninitialized ();
   if (cond_expr
-      && !integer_truep (cond_expr)
+      && EXPR_P (cond_expr)
       && (version_niter
 	  || version_align
 	  || version_alias
@@ -3684,6 +3684,7 @@ vect_loop_versioning (loop_vec_info loop_vinfo,
   if (cost_name && TREE_CODE (cost_name) == SSA_NAME)
     {
       gimple *def = SSA_NAME_DEF_STMT (cost_name);
+      gcc_assert (gimple_bb (def) == condition_bb);
       /* All uses of the cost check are 'true' after the check we
 	 are going to insert.  */
       replace_uses_by (cost_name, boolean_true_node);