diff options
Diffstat (limited to 'gcc-4.6/gcc/tree-ssa-alias.c')
| -rw-r--r-- | gcc-4.6/gcc/tree-ssa-alias.c | 25 |
1 files changed, 20 insertions, 5 deletions
diff --git a/gcc-4.6/gcc/tree-ssa-alias.c b/gcc-4.6/gcc/tree-ssa-alias.c index f4c38e1..e3bb3a8 100644 --- a/gcc-4.6/gcc/tree-ssa-alias.c +++ b/gcc-4.6/gcc/tree-ssa-alias.c @@ -1216,8 +1216,20 @@ ref_maybe_used_by_call_p_1 (gimple call, ao_ref *ref) && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL) switch (DECL_FUNCTION_CODE (callee)) { - /* All the following functions clobber memory pointed to by - their first argument. */ + /* All the following functions read memory pointed to by + their second argument. strcat/strncat additionally + reads memory pointed to by the first argument. */ + case BUILT_IN_STRCAT: + case BUILT_IN_STRNCAT: + { + ao_ref dref; + ao_ref_init_from_ptr_and_size (&dref, + gimple_call_arg (call, 0), + NULL_TREE); + if (refs_may_alias_p_1 (&dref, ref, false)) + return true; + } + /* FALLTHRU */ case BUILT_IN_STRCPY: case BUILT_IN_STRNCPY: case BUILT_IN_MEMCPY: @@ -1225,8 +1237,6 @@ ref_maybe_used_by_call_p_1 (gimple call, ao_ref *ref) case BUILT_IN_MEMPCPY: case BUILT_IN_STPCPY: case BUILT_IN_STPNCPY: - case BUILT_IN_STRCAT: - case BUILT_IN_STRNCAT: { ao_ref dref; tree size = NULL_TREE; @@ -1457,7 +1467,12 @@ call_may_clobber_ref_p_1 (gimple call, ao_ref *ref) { ao_ref dref; tree size = NULL_TREE; - if (gimple_call_num_args (call) == 3) + /* Don't pass in size for strncat, as the maximum size + is strlen (dest) + n + 1 instead of n, resp. + n + 1 at dest + strlen (dest), but strlen (dest) isn't + known. */ + if (gimple_call_num_args (call) == 3 + && DECL_FUNCTION_CODE (callee) != BUILT_IN_STRNCAT) size = gimple_call_arg (call, 2); ao_ref_init_from_ptr_and_size (&dref, gimple_call_arg (call, 0), |