From 01d28c3ff91870a620f7a5a699e509e103afb8b9 Mon Sep 17 00:00:00 2001 From: Jason Merrill Date: Thu, 2 Oct 2003 13:43:57 -0400 Subject: correct comment From-SVN: r72042 --- gcc/alias.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) (limited to 'gcc/alias.c') diff --git a/gcc/alias.c b/gcc/alias.c index 19ac3f78655..797c3f5cd97 100644 --- a/gcc/alias.c +++ b/gcc/alias.c @@ -48,7 +48,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA different alias sets cannot alias each other, with one important exception. Consider something like: - struct S {int i; double d; }; + struct S { int i; double d; }; a store to an `S' can alias something of either type `int' or type `double'. (However, a store to an `int' cannot alias a `double' @@ -604,11 +604,15 @@ new_alias_set (void) return 0; } -/* Indicate that things in SUBSET can alias things in SUPERSET, but - not vice versa. For example, in C, a store to an `int' can alias a - structure containing an `int', but not vice versa. Here, the - structure would be the SUPERSET and `int' the SUBSET. This - function should be called only once per SUPERSET/SUBSET pair. +/* Indicate that things in SUBSET can alias things in SUPERSET, but that + not everything that aliases SUPERSET also aliases SUBSET. For example, + in C, a store to an `int' can alias a load of a structure containing an + `int', and vice versa. But it can't alias a load of a 'double' member + of the same structure. Here, the structure would be the SUPERSET and + `int' the SUBSET. This relationship is also described in the comment at + the beginning of this file. + + This function should be called only once per SUPERSET/SUBSET pair. It is illegal for SUPERSET to be zero; everything is implicitly a subset of alias set zero. */ -- cgit v1.2.1