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| author | Jeff Law <law@redhat.com> | 2005-01-31 20:48:52 -0700 |
|---|---|---|
| committer | Jeff Law <law@gcc.gnu.org> | 2005-01-31 20:48:52 -0700 |
| commit | dc5d4efbce3e6587b31da8d6d1c502aea80acfcc (patch) | |
| tree | 156482e0e2154f02927d2baaf5e214e13f2ba2d8 /gcc/fold-const.c | |
| parent | 3dcec1e9e797af50ef38718cf19e0742e1c6a96a (diff) | |
| download | gcc-dc5d4efbce3e6587b31da8d6d1c502aea80acfcc.zip gcc-dc5d4efbce3e6587b31da8d6d1c502aea80acfcc.tar.gz gcc-dc5d4efbce3e6587b31da8d6d1c502aea80acfcc.tar.bz2 | |
fold-const.c (fold, [...]): Do not lose side effects when optimizing 0 % X.
* fold-const.c (fold, case CEIL_MOD_EXPR): Do not lose side
effects when optimizing 0 % X. Do not try to optimize X % 0.
* gcc.c-torture/execute/20050131-1.c: New test.
* gcc.dg/wcaselabel.c: New test.
From-SVN: r94516
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 13c57e0..2285742 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -7938,12 +7938,21 @@ fold (tree expr) case FLOOR_MOD_EXPR: case ROUND_MOD_EXPR: case TRUNC_MOD_EXPR: - /* 0 % X is always zero as is X % 1. */ - if (integer_zerop (arg0) || integer_onep (arg1)) + /* X % 1 is always zero, but be sure to preserve any side + effects in X. */ + if (integer_onep (arg1)) return omit_one_operand (type, integer_zero_node, arg0); + + /* X % 0, return X % 0 unchanged so that we can get the + proper warnings and errors. */ if (integer_zerop (arg1)) return t; + /* 0 % X is always zero, but be sure to preserve any side + effects in X. Place this after checking for X == 0. */ + if (integer_zerop (arg0)) + return omit_one_operand (type, integer_zero_node, arg1); + /* X % -1 is zero. */ if (!TYPE_UNSIGNED (type) && TREE_CODE (arg1) == INTEGER_CST |