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| author | Joseph Myers <joseph@codesourcery.com> | 2009-10-23 13:18:42 +0100 |
|---|---|---|
| committer | Joseph Myers <jsm28@gcc.gnu.org> | 2009-10-23 13:18:42 +0100 |
| commit | cb9c2485b2487ee5aa9a3e1b75385c508d28519f (patch) | |
| tree | 0fe23e5ff51a04afd7bc7b9f279e3b3b20be309d /gcc/c-common.c | |
| parent | 93f28ca73fbb038d98a74a464d04c734743720c4 (diff) | |
| download | gcc-cb9c2485b2487ee5aa9a3e1b75385c508d28519f.zip gcc-cb9c2485b2487ee5aa9a3e1b75385c508d28519f.tar.gz gcc-cb9c2485b2487ee5aa9a3e1b75385c508d28519f.tar.bz2 | |
re PR c/41673 (variable-length array dereference inside sizeof gives "warning: dereferencing type-punned pointer will break strict-aliasing rules")
PR c/41673
* alias.c (get_alias_set): Call langhook before returning 0 for
types with structural equality.
* c-common.c (c_common_get_alias_set): Use alias set of element
type for arrays with structural comparison.
testsuite:
* gcc.dg/Wstrict-aliasing-bogus-vla-1.c: New test.
From-SVN: r153496
Diffstat (limited to 'gcc/c-common.c')
| -rw-r--r-- | gcc/c-common.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/gcc/c-common.c b/gcc/c-common.c index 16e17b3..8a6d15b 100644 --- a/gcc/c-common.c +++ b/gcc/c-common.c @@ -4183,6 +4183,15 @@ c_common_get_alias_set (tree t) tree u; PTR *slot; + /* For VLAs, use the alias set of the element type rather than the + default of alias set 0 for types compared structurally. */ + if (TYPE_P (t) && TYPE_STRUCTURAL_EQUALITY_P (t)) + { + if (TREE_CODE (t) == ARRAY_TYPE) + return get_alias_set (TREE_TYPE (t)); + return -1; + } + /* Permit type-punning when accessing a union, provided the access is directly through the union. For example, this code does not permit taking the address of a union member and then storing |