diff options
Diffstat (limited to 'gcc/rtl.h')
| -rw-r--r-- | gcc/rtl.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/gcc/rtl.h b/gcc/rtl.h index 39f121be426..b6d505a50f0 100644 --- a/gcc/rtl.h +++ b/gcc/rtl.h @@ -347,7 +347,10 @@ struct GTY((chain_next ("RTX_NEXT (&%h)"), unsigned return_val : 1; union { - /* RTXs are free to use up to 32 bit from here. */ + /* The final union field is aligned to 64 bits on LP64 hosts, + giving a 32-bit gap after the fields above. We optimize the + layout for that case and use the gap for extra code-specific + information. */ /* In a CONST_WIDE_INT (aka hwivec_def), this is the number of HOST_WIDE_INTs in the hwivec_def. */ |