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re PR c/64610 (No -Wbool-compare warning on "(0 != a) >= 0") 

PR c/64610
	* c-common.c (maybe_warn_bool_compare): Warn when comparing a boolean
	with 0/1.

	* c-c++-common/Wbool-compare-1.c (fn1): Remove a few lines.
	* c-c++-common/Wbool-compare-2.c: New test.

From-SVN: r222587
This commit is contained in:
Marek Polacek 2015-04-29 18:13:44 +00:00 committed by Marek Polacek
parent d28ad5d4c5
commit 716c0ba6bf
5 changed files with 126 additions and 7 deletions
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6
gcc/c-family/ChangeLog
View File

@ -1,3 +1,9 @@
2015-04-29 Marek Polacek <polacek@redhat.com>
PR c/64610
* c-common.c (maybe_warn_bool_compare): Warn when comparing a boolean
with 0/1.
2015-04-29 Jakub Jelinek <jakub@redhat.com>
* c-common.h (omp_clause_mask): Unconditionally define as a class.

16
gcc/c-family/c-common.c
View File

@ -11910,8 +11910,8 @@ maybe_warn_bool_compare (location_t loc, enum tree_code code, tree op0,
if (!integer_zerop (cst) && !integer_onep (cst))
{
int sign = (TREE_CODE (op0) == INTEGER_CST)
? tree_int_cst_sgn (cst) : -tree_int_cst_sgn (cst);
int sign = (TREE_CODE (op0) == INTEGER_CST
? tree_int_cst_sgn (cst) : -tree_int_cst_sgn (cst));
if (code == EQ_EXPR
|| ((code == GT_EXPR || code == GE_EXPR) && sign < 0)
|| ((code == LT_EXPR || code == LE_EXPR) && sign > 0))
@ -11921,6 +11921,18 @@ maybe_warn_bool_compare (location_t loc, enum tree_code code, tree op0,
warning_at (loc, OPT_Wbool_compare, "comparison of constant %qE "
"with boolean expression is always true", cst);
}
else if (integer_zerop (cst) || integer_onep (cst))
{
/* Do some magic to get the right diagnostics. */
bool flag = TREE_CODE (op0) == INTEGER_CST;
flag = integer_zerop (cst) ? flag : !flag;
if ((code == GE_EXPR && !flag) || (code == LE_EXPR && flag))
warning_at (loc, OPT_Wbool_compare, "comparison of constant %qE "
"with boolean expression is always true", cst);
else if ((code == LT_EXPR && !flag) || (code == GT_EXPR && flag))
warning_at (loc, OPT_Wbool_compare, "comparison of constant %qE "
"with boolean expression is always false", cst);
}
}
/* The C and C++ parsers both use vectors to hold function arguments.

6
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,9 @@
2015-04-29 Marek Polacek <polacek@redhat.com>
PR c/64610
* c-c++-common/Wbool-compare-1.c (fn1): Remove a few lines.
* c-c++-common/Wbool-compare-2.c: New test.
2015-04-29 Alan Lawrence <alan.lawrence@arm.com>
PR target/65770

5
gcc/testsuite/c-c++-common/Wbool-compare-1.c
View File

@ -72,15 +72,10 @@ fn1 (bool b)
r = b == true;
r = b != true;
/* Some of these don't make much sense, but we don't warn. */
r = b < false;
r = b >= false;
r = b <= false;
r = b > false;
r = b < true;
r = b >= true;
r = b <= true;
r = b > true;
}
void

100
gcc/testsuite/c-c++-common/Wbool-compare-2.c Normal file
View File

@ -0,0 +1,100 @@
/* PR c/64610 */
/* { dg-do compile } */
/* { dg-options "-Wbool-compare" } */
#ifndef __cplusplus
# define bool _Bool
# define true 1
# define false 0
#endif
extern bool foo (void);
enum { A, B };
int
fn1 (bool b)
{
int r = 0;
r += b >= 0; /* { dg-warning "with boolean expression is always true" } */
r += b > 0;
r += b < 0; /* { dg-warning "with boolean expression is always false" } */
r += b <= 0;
r += b >= 1;
r += b > 1; /* { dg-warning "with boolean expression is always false" } */
r += b < 1;
r += b <= 1; /* { dg-warning "with boolean expression is always true" } */
r += foo () >= 0; /* { dg-warning "with boolean expression is always true" } */
r += foo () > 0;
r += foo () < 0; /* { dg-warning "with boolean expression is always false" } */
r += foo () <= 0;
r += foo () >= 1;
r += foo () > 1; /* { dg-warning "with boolean expression is always false" } */
r += foo () < 1;
r += foo () <= 1; /* { dg-warning "with boolean expression is always true" } */
r += b >= A; /* { dg-warning "with boolean expression is always true" } */
r += b > A;
r += b < A; /* { dg-warning "with boolean expression is always false" } */
r += b <= A;
r += b >= B;
r += b > B; /* { dg-warning "with boolean expression is always false" } */
r += b < B;
r += b <= B; /* { dg-warning "with boolean expression is always true" } */
/* Swap LHS and RHS. */
r += 0 >= b;
r += 0 > b; /* { dg-warning "with boolean expression is always false" } */
r += 0 < b;
r += 0 <= b; /* { dg-warning "with boolean expression is always true" } */
r += 1 >= b; /* { dg-warning "with boolean expression is always true" } */
r += 1 > b;
r += 1 < b; /* { dg-warning "with boolean expression is always false" } */
r += 1 <= b;
r += 0 >= foo ();
r += 0 > foo (); /* { dg-warning "with boolean expression is always false" } */
r += 0 < foo ();
r += 0 <= foo (); /* { dg-warning "with boolean expression is always true" } */
r += 1 >= foo (); /* { dg-warning "with boolean expression is always true" } */
r += 1 > foo ();
r += 1 < foo (); /* { dg-warning "with boolean expression is always false" } */
r += 1 <= foo ();
r += A >= b;
r += A > b; /* { dg-warning "with boolean expression is always false" } */
r += A < b;
r += A <= b; /* { dg-warning "with boolean expression is always true" } */
r += B >= b; /* { dg-warning "with boolean expression is always true" } */
r += B > b;
r += B < b; /* { dg-warning "with boolean expression is always false" } */
r += B <= b;
return r;
}
int
fn2 (int i, int j)
{
int r = 0;
r += (i == j) >= 0; /* { dg-warning "with boolean expression is always true" } */
r += (i == j) > 0;
r += (i == j) < 0; /* { dg-warning "with boolean expression is always false" } */
r += (i == j) <= 0;
r += (i == j) >= 1;
r += (i == j) > 1; /* { dg-warning "with boolean expression is always false" } */
r += (i == j) < 1;
r += (i == j) <= 1; /* { dg-warning "with boolean expression is always true" } */
return r;
}