[PATCH] Fixup tree_nop_conversion_p WRT BLKmode vector types

[Richard Biener]

This special-cases BLKmode vector types appropriately.

Bootstrapped and tested on x86_64-unknown-linux-gnu.

OK?

        * tree.cc (tree_nop_conversion_p): Special case two BLKmode
        types.
---
 gcc/tree.cc | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/gcc/tree.cc b/gcc/tree.cc
index 19069eb5960..52313fbd129 100644
--- a/gcc/tree.cc
+++ b/gcc/tree.cc
@@ -12462,6 +12462,19 @@ tree_nop_conversion_p (const_tree outer_type, 
const_tree inner_type)
          || TREE_CODE (inner_type) == OFFSET_TYPE))
     return TYPE_PRECISION (outer_type) == TYPE_PRECISION (inner_type);
 
+  if (TYPE_MODE (outer_type) == BLKmode
+      && TYPE_MODE (inner_type) == BLKmode)
+    {
+      if (VECTOR_TYPE_P (outer_type)
+         && VECTOR_TYPE_P (inner_type)
+         && known_eq (TYPE_VECTOR_SUBPARTS (outer_type),
+                      TYPE_VECTOR_SUBPARTS (inner_type))
+         && (TYPE_MODE (TREE_TYPE (outer_type))
+             == TYPE_MODE (TREE_TYPE (inner_type))))
+       return true;
+      return false;
+    }
+
   /* Otherwise fall back on comparing machine modes (e.g. for
      aggregate types, floats).  */
   return TYPE_MODE (outer_type) == TYPE_MODE (inner_type);
-- 
2.51.0