[gcc r11-8830] c/101512 - fix missing address-taking in c_common_mark_addressable_vec

[gcc r11-8830] c/101512 - fix missing address-taking in c_common_mark_addressable_vec

[Richard Biener]

https://gcc.gnu.org/g:129bf4f2efc0ec22ee14affd8c8a3bfe07896356

commit r11-8830-g129bf4f2efc0ec22ee14affd8c8a3bfe07896356
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Jul 21 09:14:24 2021 +0200

    c/101512 - fix missing address-taking in c_common_mark_addressable_vec
    
    c_common_mark_addressable_vec fails to look through C_MAYBE_CONST_EXPR
    in the case it isn't at the toplevel.
    
    2021-07-21  Richard Biener  <rguenther@suse.de>
    
            PR c/101512
    gcc/c-family/
            * c-common.c (c_common_mark_addressable_vec): Look through
            C_MAYBE_CONST_EXPR even if not at the toplevel.
    
    gcc/testsuite/
            * gcc.dg/torture/pr101512.c: New testcase.
    
    (cherry picked from commit e63d76234d18cac731c4f3610d513bd8b39b5520)

Diff:
---
 gcc/c-family/c-common.c                 | 11 +++++++----
 gcc/testsuite/gcc.dg/torture/pr101512.c | 11 +++++++++++
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index d227686a030..a2809e79158 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -6759,10 +6759,13 @@ complete_flexible_array_elts (tree init)
 void 
 c_common_mark_addressable_vec (tree t)
 {   
-  if (TREE_CODE (t) == C_MAYBE_CONST_EXPR)
-    t = C_MAYBE_CONST_EXPR_EXPR (t);
-  while (handled_component_p (t))
-    t = TREE_OPERAND (t, 0);
+  while (handled_component_p (t) || TREE_CODE (t) == C_MAYBE_CONST_EXPR)
+    {
+      if (TREE_CODE (t) == C_MAYBE_CONST_EXPR)
+	t = C_MAYBE_CONST_EXPR_EXPR (t);
+      else
+	t = TREE_OPERAND (t, 0);
+    }
   if (!VAR_P (t)
       && TREE_CODE (t) != PARM_DECL
       && TREE_CODE (t) != COMPOUND_LITERAL_EXPR)
diff --git a/gcc/testsuite/gcc.dg/torture/pr101512.c b/gcc/testsuite/gcc.dg/torture/pr101512.c
new file mode 100644
index 00000000000..a25da2aa0b5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr101512.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-w -Wno-psabi" } */
+
+int n();
+typedef unsigned long V __attribute__ ((vector_size (64)));
+V
+foo (int i, V v)
+{
+  i = ((V)(V){n()})[n()];
+  return v + i;
+}