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fold-const.c (fold_negate_expr): Don't fold INTEGER_CST if that overflows when SANITIZE_SI_OVERFLOW is on. 

* fold-const.c (fold_negate_expr): Don't fold INTEGER_CST if
	that overflows when SANITIZE_SI_OVERFLOW is on.  Guard -(-A)
	folding with TYPE_OVERFLOW_SANITIZED.

	* c-c++-common/ubsan/overflow-negate-3.c: New test.

From-SVN: r217556
This commit is contained in:
Marek Polacek 2014-11-14 11:57:05 +00:00 committed by Marek Polacek
parent 4088b790cc
commit c7274165bd
4 changed files with 36 additions and 2 deletions
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6
gcc/ChangeLog
View File

@ -1,3 +1,9 @@
2014-11-14 Marek Polacek <polacek@redhat.com>
* fold-const.c (fold_negate_expr): Don't fold INTEGER_CST if
that overflows when SANITIZE_SI_OVERFLOW is on. Guard -(-A)
folding with TYPE_OVERFLOW_SANITIZED.
2014-11-14 Marek Polacek <polacek@redhat.com>
PR sanitizer/63839

7
gcc/fold-const.c
View File

@ -554,7 +554,8 @@ fold_negate_expr (location_t loc, tree t)
case INTEGER_CST:
tem = fold_negate_const (t, type);
if (TREE_OVERFLOW (tem) == TREE_OVERFLOW (t)
|| !TYPE_OVERFLOW_TRAPS (type))
|| (!TYPE_OVERFLOW_TRAPS (type)
&& (flag_sanitize & SANITIZE_SI_OVERFLOW) == 0))
return tem;
break;
@ -611,7 +612,9 @@ fold_negate_expr (location_t loc, tree t)
break;
case NEGATE_EXPR:
return TREE_OPERAND (t, 0);
if (!TYPE_OVERFLOW_SANITIZED (type))
return TREE_OPERAND (t, 0);
break;
case PLUS_EXPR:
if (!HONOR_SIGN_DEPENDENT_ROUNDING (TYPE_MODE (type))

4
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,7 @@
2014-11-14 Marek Polacek <polacek@redhat.com>
* c-c++-common/ubsan/overflow-negate-3.c: New test.
2014-11-14 Marek Polacek <polacek@redhat.com>
PR sanitizer/63839

21
gcc/testsuite/c-c++-common/ubsan/overflow-negate-3.c Normal file
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@ -0,0 +1,21 @@
/* { dg-do run } */
/* { dg-options "-fsanitize=signed-integer-overflow" } */
#define INT_MIN (-__INT_MAX__ - 1)
int
main ()
{
int x = INT_MIN;
int y;
asm ("" : "+g" (x));
y = -(-x);
asm ("" : "+g" (y));
y = -(-INT_MIN);
asm ("" : "+g" (y));
}
/* { dg-output "negation of -2147483648 cannot be represented in type 'int'\[^\n\r]*; cast to an unsigned type to negate this value to itself\[^\n\r]*(\n|\r\n|\r)" } */
/* { dg-output "\[^\n\r]*negation of -2147483648 cannot be represented in type 'int'\[^\n\r]*; cast to an unsigned type to negate this value to itself\[^\n\r]*(\n|\r\n|\r)" } */
/* { dg-output "\[^\n\r]*negation of -2147483648 cannot be represented in type 'int'\[^\n\r]*; cast to an unsigned type to negate this value to itself\[^\n\r]*(\n|\r\n|\r)" } */
/* { dg-output "\[^\n\r]*negation of -2147483648 cannot be represented in type 'int'\[^\n\r]*; cast to an unsigned type to negate this value to itself\[^\n\r]*(\n|\r\n|\r)" } */