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| author | Ian Lance Taylor <iant@google.com> | 2007-01-05 19:05:46 +0000 |
|---|---|---|
| committer | Ian Lance Taylor <ian@gcc.gnu.org> | 2007-01-05 19:05:46 +0000 |
| commit | b3c6d2ea006d4c688964c044a081ddea7884148a (patch) | |
| tree | 5758b8cb24576b1e3eb71016f81cfeab25bbd494 /gcc/c-common.c | |
| parent | 97af925ba7b16e64c9f8b48cbfd5b4ccaa905f36 (diff) | |
| download | gcc-b3c6d2ea006d4c688964c044a081ddea7884148a.zip gcc-b3c6d2ea006d4c688964c044a081ddea7884148a.tar.gz gcc-b3c6d2ea006d4c688964c044a081ddea7884148a.tar.bz2 | |
c-common.c (decl_with_nonnull_addr_p): New function.
./: * c-common.c (decl_with_nonnull_addr_p): New function.
(c_common_truthvalue_conversion): Call it.
* c-typeck.c (build_binary_op): Likewise.
* c-common.h (decl_with_nonnull_addr_p): Declare.
cp/:
* typeck.c (build_binary_op): Warn about comparing a non-weak
address to NULL.
testsuite/:
* gcc.dg/Walways-true-1.c: New test.
* gcc.dg/Walways-true-2.c: New test.
* g++.dg/warn/Walways-true-1.C: New test.
* g++.dg/warn/Walways-true-2.C: New test.
From-SVN: r120493
Diffstat (limited to 'gcc/c-common.c')
| -rw-r--r-- | gcc/c-common.c | 35 |
1 files changed, 23 insertions, 12 deletions
diff --git a/gcc/c-common.c b/gcc/c-common.c index 2fd2a81..1794bd8 100644 --- a/gcc/c-common.c +++ b/gcc/c-common.c @@ -2591,6 +2591,18 @@ pointer_int_sum (enum tree_code resultcode, tree ptrop, tree intop) return fold_build2 (resultcode, result_type, ptrop, intop); } +/* Return whether EXPR is a declaration whose address can never be + NULL. */ + +bool +decl_with_nonnull_addr_p (tree expr) +{ + return (DECL_P (expr) + && (TREE_CODE (expr) == PARM_DECL + || TREE_CODE (expr) == LABEL_DECL + || !DECL_WEAK (expr))); +} + /* Prepare expr to be an argument of a TRUTH_NOT_EXPR, or for an `if' or `while' statement or ?..: exp. It should already have been validated to be of suitable type; otherwise, a bad @@ -2656,23 +2668,22 @@ c_common_truthvalue_conversion (tree expr) case ADDR_EXPR: { tree inner = TREE_OPERAND (expr, 0); - if (DECL_P (inner) - && (TREE_CODE (inner) == PARM_DECL - || TREE_CODE (inner) == LABEL_DECL - || !DECL_WEAK (inner))) + if (decl_with_nonnull_addr_p (inner)) { - /* Common Ada/Pascal programmer's mistake. We always warn - about this since it is so bad. */ - warning (OPT_Walways_true, "the address of %qD will always evaluate as %<true%>", + /* Common Ada/Pascal programmer's mistake. */ + warning (OPT_Walways_true, + "the address of %qD will always evaluate as %<true%>", inner); return truthvalue_true_node; } - /* If we are taking the address of an external decl, it might be - zero if it is weak, so we cannot optimize. */ - if (DECL_P (inner) - && DECL_EXTERNAL (inner)) - break; + /* If we still have a decl, it is possible for its address to + be NULL, so we cannot optimize. */ + if (DECL_P (inner)) + { + gcc_assert (DECL_WEAK (inner)); + break; + } if (TREE_SIDE_EFFECTS (inner)) return build2 (COMPOUND_EXPR, truthvalue_type_node, |