diff options
| author | Richard Kenner <kenner@gcc.gnu.org> | 1993-07-05 17:55:06 -0400 |
|---|---|---|
| committer | Richard Kenner <kenner@gcc.gnu.org> | 1993-07-05 17:55:06 -0400 |
| commit | 05a0d5eabb68d036b5717738d601abac96a46c96 (patch) | |
| tree | 1aa578f5f8f27c53c867e8d77a854a7f50cda9dd /gcc/fold-const.c | |
| parent | 40083ddf51610448fcdbb96591065678675ecbce (diff) | |
| download | gcc-05a0d5eabb68d036b5717738d601abac96a46c96.zip gcc-05a0d5eabb68d036b5717738d601abac96a46c96.tar.gz gcc-05a0d5eabb68d036b5717738d601abac96a46c96.tar.bz2 | |
(fold, case EQ_EXPR, LE_EXPR): If comparing results of signed MOD with
zero, use an unsigned MOD.
From-SVN: r4852
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 60b5e99..d03ae53 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -4163,6 +4163,25 @@ fold (expr) arg1)); } + /* If this is an NE or EQ comparison of zero against the result of a + signed MOD operation, make the MOD operation unsigned since it + is simpler and equivalent. */ + if ((code == NE_EXPR || code == EQ_EXPR) + && integer_zerop (arg1) + && ! TREE_UNSIGNED (TREE_TYPE (arg0)) + && (TREE_CODE (arg0) == TRUNC_MOD_EXPR + || TREE_CODE (arg0) == CEIL_MOD_EXPR + || TREE_CODE (arg0) == FLOOR_MOD_EXPR + || TREE_CODE (arg0) == ROUND_MOD_EXPR)) + { + tree newtype = unsigned_type (TREE_TYPE (arg0)); + tree newmod = build (TREE_CODE (arg0), newtype, + convert (newtype, TREE_OPERAND (arg0, 0)), + convert (newtype, TREE_OPERAND (arg0, 1))); + + return build (code, type, newmod, convert (newtype, arg1)); + } + /* If this is an NE comparison of zero with an AND of one, remove the comparison since the AND will give the correct value. */ if (code == NE_EXPR && integer_zerop (arg1) |