[gcc r12-837] middle-end/100582 - fix array_at_struct_end_p for vector indexing

[Richard Biener <rguenth@gcc.gnu.org>]

https://gcc.gnu.org/g:e0a5daf81f2c79a0275eccd7c1a25349990a7a4d

commit r12-837-ge0a5daf81f2c79a0275eccd7c1a25349990a7a4d
Author: Richard Biener <rguenther@suse.de>
Date:   Mon May 17 13:56:14 2021 +0200

    middle-end/100582 - fix array_at_struct_end_p for vector indexing
    
    Vector indexing leaves us with ARRAY_REFs of VIEW_CONVERT_EXPRs,
    sth which array_at_struct_end_p considers a array-at-struct-end
    even when there's an underlying decl visible.  The following fixes
    the latter.
    
    2021-05-17  Richard Biener  <rguenther@suse.de>
    
            PR middle-end/100582
            * tree.c (array_at_struct_end_p): Get to the base of the
            reference before looking for the underlying decl.
    
            * gcc.target/i386/pr100582.c: New testcase.

Diff:
---
 gcc/testsuite/gcc.target/i386/pr100582.c | 16 ++++++++++++++++
 gcc/tree.c                               |  8 +++-----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/gcc/testsuite/gcc.target/i386/pr100582.c b/gcc/testsuite/gcc.target/i386/pr100582.c
new file mode 100644
index 00000000000..9520fe7a197
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr100582.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -mavx2" } */
+
+typedef unsigned char v32qi __attribute__((vector_size(32)));
+
+v32qi
+f2 (v32qi x, v32qi a, v32qi b)
+{
+    v32qi e;
+  for (int i = 0; i != 32; i++)
+     e[i] = x[i] ? a[i] : b[i];
+
+  return e;
+}
+
+/* { dg-final { scan-assembler-times "pblendvb" 1 } } */
diff --git a/gcc/tree.c b/gcc/tree.c
index 01eda553a65..8afba598eb5 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -12550,13 +12550,11 @@ array_at_struct_end_p (tree ref)
       || ! TYPE_MAX_VALUE (TYPE_DOMAIN (atype)))
     return true;
 
-  if (TREE_CODE (ref) == MEM_REF
-      && TREE_CODE (TREE_OPERAND (ref, 0)) == ADDR_EXPR)
-    ref = TREE_OPERAND (TREE_OPERAND (ref, 0), 0);
-
   /* If the reference is based on a declared entity, the size of the array
      is constrained by its given domain.  (Do not trust commons PR/69368).  */
-  if (DECL_P (ref)
+  ref = get_base_address (ref);
+  if (ref
+      && DECL_P (ref)
       && !(flag_unconstrained_commons
 	   && VAR_P (ref) && DECL_COMMON (ref))
       && DECL_SIZE_UNIT (ref)