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c-common.c (c_common_truthvalue_conversion): Warn only for signed integer shift ops in boolean context.

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2016-10-19  Bernd Edlinger  <bernd.edlinger@hotmail.de>

        * c-common.c (c_common_truthvalue_conversion): Warn only for signed
        integer shift ops in boolean context.

testsuite:
2016-10-19  Bernd Edlinger  <bernd.edlinger@hotmail.de>

        * c-c++-common/Wint-in-bool-context-2.c: New test.

From-SVN: r241354
This commit is contained in:
Bernd Edlinger 2016-10-19 21:00:39 +00:00
parent f3070dab7a
commit 4c71237418
4 changed files with 36 additions and 3 deletions
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7
gcc/c-family/ChangeLog
View File

@ -1,4 +1,9 @@
2016-06-16 Aldy Hernandez <aldyh@redhat.com>
2016-10-19 Bernd Edlinger <bernd.edlinger@hotmail.de>
* c-common.c (c_common_truthvalue_conversion): Warn only for signed
integer shift ops in boolean context.
2016-10-18 Aldy Hernandez <aldyh@redhat.com>
* c.opt (Walloca): New.
(Walloca-larger-than=): New.

11
gcc/c-family/c-common.c
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@ -3328,8 +3328,15 @@ c_common_truthvalue_conversion (location_t location, tree expr)
TREE_OPERAND (expr, 0));
case LSHIFT_EXPR:
warning_at (EXPR_LOCATION (expr), OPT_Wint_in_bool_context,
"<< in boolean context, did you mean '<' ?");
/* We will only warn on unsigned shifts here, because the majority of
false positive warnings happen in code where unsigned arithmetic
was used in anticipation of a possible overflow.
Furthermore, if we see an unsigned type here we know that the
result of the shift is not subject to integer promotion rules. */
if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
&& !TYPE_UNSIGNED (TREE_TYPE (expr)))
warning_at (EXPR_LOCATION (expr), OPT_Wint_in_bool_context,
"<< in boolean context, did you mean '<' ?");
break;
case COND_EXPR:

4
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,7 @@
2016-10-19 Bernd Edlinger <bernd.edlinger@hotmail.de>
* c-c++-common/Wint-in-bool-context-2.c: New test.
2016-10-19 Jerry DeLisle <jvdelisle@gcc.gnu.org>
* gfortran.dg/dtio_17.f90: Fix test.

17
gcc/testsuite/c-c++-common/Wint-in-bool-context-2.c Normal file
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@ -0,0 +1,17 @@
/* { dg-options "-Wint-in-bool-context" } */
/* { dg-do compile } */
typedef unsigned u32;
typedef unsigned char u8;
#define KEYLENGTH 8
int foo (u8 plen, u32 key)
{
if ((plen < KEYLENGTH) && (key << plen)) /* { dg-bogus "boolean context" } */
return -1;
if ((plen << KEYLENGTH) && (key < plen)) /* { dg-warning "boolean context" } */
return -2;
return 0;
}