From 25ff5dd35471b2b20f2b2681c8ff24c0d086ec00 Mon Sep 17 00:00:00 2001 From: Marek Polacek Date: Mon, 5 Sep 2016 12:17:09 +0000 Subject: [PATCH] re PR c/77423 (-Wlogical-not-parentheses false positive for bitwise expression with _Bool operands) PR c/77423 * doc/invoke.texi: Update -Wlogical-not-parentheses documentation. * c-common.c (bool_promoted_to_int_p): New function. (expr_has_boolean_operands_p): New function. (warn_logical_not_parentheses): Return if expr_has_boolean_operands_p. (maybe_warn_bool_compare): Use bool_promoted_to_int_p. * c-c++-common/Wlogical-not-parentheses-3.c: New test. From-SVN: r239988 --- gcc/ChangeLog | 5 +++ gcc/c-family/ChangeLog | 8 ++++ gcc/c-family/c-common.c | 38 +++++++++++++++++-- gcc/doc/invoke.texi | 4 +- gcc/testsuite/ChangeLog | 5 +++ .../c-c++-common/Wlogical-not-parentheses-3.c | 31 +++++++++++++++ 6 files changed, 86 insertions(+), 5 deletions(-) create mode 100644 gcc/testsuite/c-c++-common/Wlogical-not-parentheses-3.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 2eb8986637f..00a552dcc95 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2016-09-05 Marek Polacek + + PR c/77423 + * doc/invoke.texi: Update -Wlogical-not-parentheses documentation. + 2016-09-05 Jakub Jelinek PR other/77421 diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog index 7a641403cda..7d60445a28f 100644 --- a/gcc/c-family/ChangeLog +++ b/gcc/c-family/ChangeLog @@ -1,3 +1,11 @@ +2016-09-05 Marek Polacek + + PR c/77423 + * c-common.c (bool_promoted_to_int_p): New function. + (expr_has_boolean_operands_p): New function. + (warn_logical_not_parentheses): Return if expr_has_boolean_operands_p. + (maybe_warn_bool_compare): Use bool_promoted_to_int_p. + 2016-09-04 Tom de Vries revert: diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c index 1a834a3735b..63b1e283628 100644 --- a/gcc/c-family/c-common.c +++ b/gcc/c-family/c-common.c @@ -1479,6 +1479,36 @@ warn_tautological_cmp (location_t loc, enum tree_code code, tree lhs, tree rhs) } } +/* Return true iff T is a boolean promoted to int. */ + +static bool +bool_promoted_to_int_p (tree t) +{ + return (CONVERT_EXPR_P (t) + && TREE_TYPE (t) == integer_type_node + && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == BOOLEAN_TYPE); +} + +/* Return true iff EXPR only contains boolean operands, or comparisons. */ + +static bool +expr_has_boolean_operands_p (tree expr) +{ + STRIP_NOPS (expr); + + if (CONVERT_EXPR_P (expr)) + return bool_promoted_to_int_p (expr); + else if (UNARY_CLASS_P (expr)) + return expr_has_boolean_operands_p (TREE_OPERAND (expr, 0)); + else if (BINARY_CLASS_P (expr)) + return (expr_has_boolean_operands_p (TREE_OPERAND (expr, 0)) + && expr_has_boolean_operands_p (TREE_OPERAND (expr, 1))); + else if (COMPARISON_CLASS_P (expr)) + return true; + else + return false; +} + /* Warn about logical not used on the left hand side operand of a comparison. This function assumes that the LHS is inside of TRUTH_NOT_EXPR. Do not warn if RHS is of a boolean type, a logical operator, or @@ -1494,6 +1524,10 @@ warn_logical_not_parentheses (location_t location, enum tree_code code, || truth_value_p (TREE_CODE (rhs))) return; + /* Don't warn for expression like !x == ~(bool1 | bool2). */ + if (expr_has_boolean_operands_p (rhs)) + return; + /* Don't warn for !x == 0 or !y != 0, those are equivalent to !(x == 0) or !(y != 0). */ if ((code == EQ_EXPR || code == NE_EXPR) @@ -12415,9 +12449,7 @@ maybe_warn_bool_compare (location_t loc, enum tree_code code, tree op0, don't want to warn here. */ tree noncst = TREE_CODE (op0) == INTEGER_CST ? op1 : op0; /* Handle booleans promoted to integers. */ - if (CONVERT_EXPR_P (noncst) - && TREE_TYPE (noncst) == integer_type_node - && TREE_CODE (TREE_TYPE (TREE_OPERAND (noncst, 0))) == BOOLEAN_TYPE) + if (bool_promoted_to_int_p (noncst)) /* Warn. */; else if (TREE_CODE (TREE_TYPE (noncst)) != BOOLEAN_TYPE && !truth_value_p (TREE_CODE (noncst))) diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 73aab7cddc8..9ab031e6a5c 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -5476,8 +5476,8 @@ if (a < 0 && a < 0) @{ @dots{} @} @opindex Wlogical-not-parentheses @opindex Wno-logical-not-parentheses Warn about logical not used on the left hand side operand of a comparison. -This option does not warn if the RHS operand is of a boolean type. Its -purpose is to detect suspicious code like the following: +This option does not warn if the right operand is considered to be a Boolean +expression. Its purpose is to detect suspicious code like the following: @smallexample int a; @dots{} diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 79ef275a01d..e54fc2ff7fe 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2016-09-05 Marek Polacek + + PR c/77423 + * c-c++-common/Wlogical-not-parentheses-3.c: New test. + 2016-09-04 Steven G. Kargl PR fortran/77391 diff --git a/gcc/testsuite/c-c++-common/Wlogical-not-parentheses-3.c b/gcc/testsuite/c-c++-common/Wlogical-not-parentheses-3.c new file mode 100644 index 00000000000..00aa747652b --- /dev/null +++ b/gcc/testsuite/c-c++-common/Wlogical-not-parentheses-3.c @@ -0,0 +1,31 @@ +/* PR c/77423 */ +/* { dg-do compile } */ +/* { dg-options "-Wlogical-not-parentheses" } */ + +#ifndef __cplusplus +# define bool _Bool +#endif + +int +f (int a, bool b, bool c) +{ + int r = 0; + + r += !a == (b | c); + r += !a == (b ^ c); + r += !a == (b & c); + r += !a == ~b; + r += !a == ~(int) b; + r += !a == ((b & c) | c); + r += !a == ((b & c) | (b ^ c)); + r += !a == (int) (b ^ c); + r += !a == (int) ~b; + r += !a == ~~b; + r += !a == ~(b | c); + r += !a == ~(b | (a == 1)); + r += !a == ~(a == 1); + + r += !a == ((b & c) | (b ^ a)); /* { dg-warning "logical not is only applied to the left hand side of comparison" } */ + + return r; +} -- 2.30.2