[gcc r14-9665] tree-optimization/114464 - verify types in recurrence vectorization

[Richard Biener]

https://gcc.gnu.org/g:226a220d0056396e825e12435cc0da52cbd5ac56

commit r14-9665-g226a220d0056396e825e12435cc0da52cbd5ac56
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Mar 26 09:39:30 2024 +0100

    tree-optimization/114464 - verify types in recurrence vectorization
    
    The following adds missing verification of vector type compatibility
    to recurrence vectorization.
    
            PR tree-optimization/114464
            * tree-vect-loop.cc (vectorizable_recurr): Verify the latch
            vector type is compatible with what we chose for the recurrence.
    
            * g++.dg/vect/pr114464.cc: New testcase.

Diff:
---
 gcc/testsuite/g++.dg/vect/pr114464.cc | 11 +++++++++++
 gcc/tree-vect-loop.cc                 | 22 ++++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/gcc/testsuite/g++.dg/vect/pr114464.cc b/gcc/testsuite/g++.dg/vect/pr114464.cc
new file mode 100644
index 00000000000..0d872aae9d4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/vect/pr114464.cc
@@ -0,0 +1,11 @@
+// { dg-do compile }
+
+void h(unsigned char *scratch, bool carry)
+{
+  for (int i = 0; i < 16; i++) {
+    bool b = scratch[i] <<= 1;
+    if (carry)
+      scratch[i] |= 1;
+    carry = b;
+  }
+}
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 2921a9e6aa1..f33629e9b04 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -9197,6 +9197,28 @@ vectorizable_recurr (loop_vec_info loop_vinfo, stmt_vec_info stmt_info,
 		return false;
 	      }
 	}
+
+      /* Verify we have set up compatible types.  */
+      edge le = loop_latch_edge (LOOP_VINFO_LOOP (loop_vinfo));
+      tree latch_vectype = NULL_TREE;
+      if (slp_node)
+	{
+	  slp_tree latch_def = SLP_TREE_CHILDREN (slp_node)[le->dest_idx];
+	  latch_vectype = SLP_TREE_VECTYPE (latch_def);
+	}
+      else
+	{
+	  tree latch_def = PHI_ARG_DEF_FROM_EDGE (phi, le);
+	  if (TREE_CODE (latch_def) == SSA_NAME)
+	    {
+	      stmt_vec_info latch_def_info = loop_vinfo->lookup_def (latch_def);
+	      latch_def_info = vect_stmt_to_vectorize (latch_def_info);
+	      latch_vectype = STMT_VINFO_VECTYPE (latch_def_info);
+	    }
+	}
+      if (!types_compatible_p (latch_vectype, vectype))
+	return false;
+
       /* The recurrence costs the initialization vector and one permute
 	 for each copy.  */
       unsigned prologue_cost = record_stmt_cost (cost_vec, 1, scalar_to_vec,