procyberian/gcc
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

re PR middle-end/36548 (remainder gives the wrong result for wrapping case with unsigned types)

Browse source 
2008-08-22  Richard Guenther  <rguenther@suse.de>

	PR middle-end/36548
	PR middle-end/37125
	* fold-const.c (extract_muldiv_1): Optimize (X * C1) % C2 only
	if the multiplication does not overflow.

	* gcc.c-torture/execute/pr37125.c: New testcase.

From-SVN: r139450
This commit is contained in:
Richard Guenther 2008-08-22 12:43:49 +00:00 • committed by Richard Biener
parent da2f5d14df
commit beeab17c6e
4 changed files with 48 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
gcc/ChangeLog
View file

@ -1,3 +1,10 @@
2008-08-22 Richard Guenther <rguenther@suse.de>
PR middle-end/36548
PR middle-end/37125
* fold-const.c (extract_muldiv_1): Optimize (X * C1) % C2 only
if the multiplication does not overflow.
2008-08-21 Nathan Sidwell <nathan@codesourcery.com>
* c-ppoutput.c (init_pp_output): Initialize src_line to 1.

13
gcc/fold-const.c
View file

@ -5930,9 +5930,20 @@ extract_muldiv_1 (tree t, tree c, enum tree_code code, tree wide_type,
(C * 8) % 4 since we know that's zero. */
if ((code == TRUNC_MOD_EXPR || code == CEIL_MOD_EXPR
|| code == FLOOR_MOD_EXPR || code == ROUND_MOD_EXPR)
/* If the multiplication can overflow we cannot optimize this.
??? Until we can properly mark individual operations as
not overflowing we need to treat sizetype special here as
stor-layout relies on this opimization to make
DECL_FIELD_BIT_OFFSET always a constant. */
&& (TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (t))
|| (TREE_CODE (TREE_TYPE (t)) == INTEGER_TYPE
&& TYPE_IS_SIZETYPE (TREE_TYPE (t))))
&& TREE_CODE (TREE_OPERAND (t, 1)) == INTEGER_CST
&& integer_zerop (const_binop (TRUNC_MOD_EXPR, op1, c, 0)))
return omit_one_operand (type, integer_zero_node, op0);
{
*strict_overflow_p = true;
return omit_one_operand (type, integer_zero_node, op0);
}
/* ... fall through ... */

6
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,9 @@
2008-08-22 Richard Guenther <rguenther@suse.de>
PR middle-end/36548
PR middle-end/37125
* gcc.c-torture/execute/pr37125.c: New testcase.
2008-08-22 Daniel Kraft <d@domob.eu>
* gfortran.dg/used_before_typed_4.f90: New test.

23
gcc/testsuite/gcc.c-torture/execute/pr37125.c Normal file
View file

@ -0,0 +1,23 @@
extern void abort (void);
static inline unsigned int
mod_rhs(int rhs)
{
if (rhs == 0) return 1;
return rhs;
}
void func_44 (unsigned int p_45);
void func_44 (unsigned int p_45)
{
if (!((p_45 * -9) % mod_rhs (-9))) {
abort();
}
}
int main (void)
{
func_44 (2);
return 0;
}