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| author | Richard Guenther <rguenther@suse.de> | 2008-08-22 12:43:49 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2008-08-22 12:43:49 +0000 |
| commit | beeab17c6ed0733203002932c08d1d3f3fe5d053 (patch) | |
| tree | 3d71422e6cc09e286c8804aef278b4add145989a | |
| parent | da2f5d14dfc05f9a9527ea3e0700a345857a83bc (diff) | |
| download | gcc-beeab17c6ed0733203002932c08d1d3f3fe5d053.zip gcc-beeab17c6ed0733203002932c08d1d3f3fe5d053.tar.gz gcc-beeab17c6ed0733203002932c08d1d3f3fe5d053.tar.bz2 | |
re PR middle-end/36548 (remainder gives the wrong result for wrapping case with unsigned types)
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
| -rw-r--r-- | gcc/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/fold-const.c | 13 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.c-torture/execute/pr37125.c | 23 |
4 files changed, 48 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index f788ef8..592b28c 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -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. diff --git a/gcc/fold-const.c b/gcc/fold-const.c index cba8826..e6769a6 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -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 ... */ diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index ae16c70..061c219 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -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. diff --git a/gcc/testsuite/gcc.c-torture/execute/pr37125.c b/gcc/testsuite/gcc.c-torture/execute/pr37125.c new file mode 100644 index 0000000..f29209e --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/pr37125.c @@ -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; +} + |