diff options
Diffstat (limited to 'gcc/tree-ssa.c')
| -rw-r--r-- | gcc/tree-ssa.c | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/gcc/tree-ssa.c b/gcc/tree-ssa.c index fb692f8..eed15c6 100644 --- a/gcc/tree-ssa.c +++ b/gcc/tree-ssa.c @@ -1411,6 +1411,10 @@ warn_uninit (tree t, const char *gmsgid, void *data) if (TREE_NO_WARNING (var)) return; + /* Do not warn if it can be initialized outside this module. */ + if (is_global_var (var)) + return; + location = (context != NULL && gimple_has_location (context)) ? gimple_location (context) : DECL_SOURCE_LOCATION (var); @@ -1443,8 +1447,46 @@ warn_uninitialized_var (tree *tp, int *walk_subtrees, void *data_) struct walk_data *data = (struct walk_data *) wi->info; tree t = *tp; + /* We do not care about LHS. */ + if (wi->is_lhs) + return NULL_TREE; + switch (TREE_CODE (t)) { + case ADDR_EXPR: + /* Taking the address of an uninitialized variable does not + count as using it. */ + *walk_subtrees = 0; + break; + + case VAR_DECL: + { + /* A VAR_DECL in the RHS of a gimple statement may mean that + this variable is loaded from memory. */ + use_operand_p vuse; + tree op; + + /* If there is not gimple stmt, + or alias information has not been computed, + then we cannot check VUSE ops. */ + if (data->stmt == NULL + || !gimple_aliases_computed_p (cfun)) + return NULL_TREE; + + vuse = SINGLE_SSA_USE_OPERAND (data->stmt, SSA_OP_VUSE); + if (vuse == NULL_USE_OPERAND_P) + return NULL_TREE; + + op = USE_FROM_PTR (vuse); + if (t != SSA_NAME_VAR (op) + || !SSA_NAME_IS_DEFAULT_DEF (op)) + return NULL_TREE; + /* If this is a VUSE of t and it is the default definition, + then warn about op. */ + t = op; + /* Fall through into SSA_NAME. */ + } + case SSA_NAME: /* We only do data flow with SSA_NAMEs, so that's all we can warn about. */ |