[gcc r16-3280] tree-optimization/121527 - wrong SRA with aggregate copy

[Richard Biener via Gcc-cvs]

https://gcc.gnu.org/g:1d0a0173cd3e48f1c7c7e98893d440527fc198d0

commit r16-3280-g1d0a0173cd3e48f1c7c7e98893d440527fc198d0
Author: Richard Biener <rguent...@suse.de>
Date:   Mon Aug 18 13:38:37 2025 +0200

    tree-optimization/121527 - wrong SRA with aggregate copy
    
    SRA handles outermost VIEW_CONVERT_EXPRs but it wrongly ignores
    those when building an access which leads to the wrong size
    used when the VIEW_CONVERT_EXPR does not have the same size as
    its operand which is valid GENERIC and is used by Ada upcasting.
    
            PR tree-optimization/121527
            * tree-sra.cc (build_access_from_expr_1): Do not strip an
            outer VIEW_CONVERT_EXPR as it's relevant for the size of
            the access.
            (get_access_for_expr): Likewise.

Diff:
---
 gcc/tree-sra.cc | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

diff --git a/gcc/tree-sra.cc b/gcc/tree-sra.cc
index 032f27704847..24ed2b2aea0e 100644
--- a/gcc/tree-sra.cc
+++ b/gcc/tree-sra.cc
@@ -1291,19 +1291,16 @@ build_access_from_expr_1 (tree expr, gimple *stmt, bool 
write)
       return NULL;
     }
 
-  /* We need to dive through V_C_Es in order to get the size of its parameter
-     and not the result type.  Ada produces such statements.  We are also
-     capable of handling the topmost V_C_E but not any of those buried in other
-     handled components.  */
-  if (TREE_CODE (expr) == VIEW_CONVERT_EXPR)
-    expr = TREE_OPERAND (expr, 0);
-
-  if (contains_view_convert_expr_p (expr))
+  /* We are capable of handling the topmost V_C_E but not any of those
+     buried in other handled components.  */
+  if (contains_view_convert_expr_p (TREE_CODE (expr) == VIEW_CONVERT_EXPR
+                                   ? TREE_OPERAND (expr, 0) : expr))
     {
       disqualify_base_of_expr (expr, "V_C_E under a different handled "
                               "component.");
       return NULL;
     }
+
   if (TREE_THIS_VOLATILE (expr))
     {
       disqualify_base_of_expr (expr, "part of a volatile reference.");
@@ -1323,6 +1320,7 @@ build_access_from_expr_1 (tree expr, gimple *stmt, bool 
write)
     case ARRAY_REF:
     case ARRAY_RANGE_REF:
     case BIT_FIELD_REF:
+    case VIEW_CONVERT_EXPR:
       ret = create_access (expr, stmt, write);
       break;
 
@@ -4086,12 +4084,6 @@ get_access_for_expr (tree expr)
   tree base;
   bool reverse;
 
-  /* FIXME: This should not be necessary but Ada produces V_C_Es with a type of
-     a different size than the size of its argument and we need the latter
-     one.  */
-  if (TREE_CODE (expr) == VIEW_CONVERT_EXPR)
-    expr = TREE_OPERAND (expr, 0);
-
   base = get_ref_base_and_extent (expr, &poffset, &psize, &pmax_size,
                                  &reverse);
   if (!known_size_p (pmax_size)