[gcc(refs/users/marxin/heads/if-to-switch-v2)] PR middle-end/90597: gcc_assert ICE in layout_type

[Martin Liska]

https://gcc.gnu.org/g:b61eaa25b0812a5996024e0ddb3535dde5a89c88

commit b61eaa25b0812a5996024e0ddb3535dde5a89c88
Author: Roger Sayle <roger@nextmovesoftware.com>
Date:   Tue Sep 1 12:03:21 2020 +0100

    PR middle-end/90597: gcc_assert ICE in layout_type
    
    This patch fixes the default implementation of TARGET_VECTOR_ALIGNMENT,
    known as default_vector_alignment, using the same logic as my earlier
    nvptx patch, as the ICE caused by TYPE_SIZE(type) being zero during
    error handling in gcc.dg/attr-vector_size.c is common among backends,
    and is known in bugzilla as PR middle-end/90597, apparently a recent
    regression.
    
    2020-09-01  Roger Sayle  <roger@nextmovesoftware.com>
    
    gcc/ChangeLog:
            PR middle-end/90597
            * targhooks.c (default_vector_alignment): Return at least the
            GET_MODE_ALIGNMENT for the type's mode.

Diff:
---
 gcc/targhooks.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/gcc/targhooks.c b/gcc/targhooks.c
index 0113c7b0ce2..da4805d284e 100644
--- a/gcc/targhooks.c
+++ b/gcc/targhooks.c
@@ -1233,8 +1233,9 @@ default_vector_alignment (const_tree type)
   tree size = TYPE_SIZE (type);
   if (tree_fits_uhwi_p (size))
     align = tree_to_uhwi (size);
-
-  return align < MAX_OFILE_ALIGNMENT ? align : MAX_OFILE_ALIGNMENT;
+  if (align >= MAX_OFILE_ALIGNMENT)
+    return MAX_OFILE_ALIGNMENT;
+  return MAX (align, GET_MODE_ALIGNMENT (TYPE_MODE (type)));
 }
 
 /* The default implementation of