[gcc r11-9993] c++: alignment of local typedef in template [PR65211]

[Jason Merrill <jason@gcc.gnu.org>]

https://gcc.gnu.org/g:e60f7127b3282e0201a1bba8ff550dc3c3fdbe61

commit r11-9993-ge60f7127b3282e0201a1bba8ff550dc3c3fdbe61
Author: Jason Merrill <jason@redhat.com>
Date:   Wed Apr 13 21:56:03 2022 -0400

    c++: alignment of local typedef in template [PR65211]
    
    Because common_handle_aligned_attribute only applies the alignment to the
    TREE_TYPE of a typedef, not the DECL_ORIGINAL_TYPE, we need to copy it
    explicitly in tsubst.
    
            PR c++/65211
    
    gcc/cp/ChangeLog:
    
            * pt.c (tsubst_decl) [TYPE_DECL]: Copy TYPE_ALIGN.
    
    gcc/testsuite/ChangeLog:
    
            * g++.target/i386/vec-tmpl1.C: New test.

Diff:
---
 gcc/cp/pt.c                               |  6 ++++++
 gcc/testsuite/g++.target/i386/vec-tmpl1.C | 17 +++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index ba505820c6a..f5154418594 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -15117,6 +15117,12 @@ tsubst_decl (tree t, tree args, tsubst_flags_t complain)
 	  {
 	    DECL_ORIGINAL_TYPE (r) = NULL_TREE;
 	    set_underlying_type (r);
+
+	    /* common_handle_aligned_attribute doesn't apply the alignment
+	       to DECL_ORIGINAL_TYPE.  */
+	    if (TYPE_USER_ALIGN (TREE_TYPE (t)))
+	      TREE_TYPE (r) = build_aligned_type (TREE_TYPE (r),
+						  TYPE_ALIGN (TREE_TYPE (t)));
 	  }
 
 	layout_decl (r, 0);
diff --git a/gcc/testsuite/g++.target/i386/vec-tmpl1.C b/gcc/testsuite/g++.target/i386/vec-tmpl1.C
new file mode 100644
index 00000000000..e0865e3515b
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/vec-tmpl1.C
@@ -0,0 +1,17 @@
+// PR c++/65211
+// { dg-additional-options "-Wno-psabi" }
+// { dg-final { scan-assembler-not "movdqa" } }
+
+typedef unsigned v4ui __attribute__ ((vector_size(16), aligned (16)));
+
+template<int I>
+static v4ui t1(unsigned *dest_data)
+{
+  typedef unsigned v4ui_1 __attribute__ ((vector_size (16), aligned (4)));
+  return ((const v4ui_1*)dest_data)[0];
+}
+
+v4ui f(unsigned int *array)
+{
+    return t1<1>(array+7);
+}