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| author | Richard Stallman <rms@gnu.org> | 1993-10-26 08:26:08 +0000 |
|---|---|---|
| committer | Richard Stallman <rms@gnu.org> | 1993-10-26 08:26:08 +0000 |
| commit | 05f3fda388756b911406c06368d76fd410d84808 (patch) | |
| tree | cacbf31471dc97fb173ff13bdd9d49737012f08d | |
| parent | fc51af1af8567e1c324e3dd62327b39dee6d1d30 (diff) | |
| download | gcc-05f3fda388756b911406c06368d76fd410d84808.zip gcc-05f3fda388756b911406c06368d76fd410d84808.tar.gz gcc-05f3fda388756b911406c06368d76fd410d84808.tar.bz2 | |
(build_binary_op): For TRUNC_MOD_EXPR and FLOOR_MOD_EXPR,
don't shorten when divisor might be -1.
From-SVN: r5893
| -rw-r--r-- | gcc/c-typeck.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/gcc/c-typeck.c b/gcc/c-typeck.c index 3c6f08b..c12f775 100644 --- a/gcc/c-typeck.c +++ b/gcc/c-typeck.c @@ -1982,7 +1982,14 @@ build_binary_op (code, orig_op0, orig_op1, convert_p) case TRUNC_MOD_EXPR: case FLOOR_MOD_EXPR: if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE) - shorten = 1; + /* Although it would be tempting to shorten always here, doing so loses + on some targets, since the modulo instruction is undefined if the + quotient can't be represented in the computation mode. We shorten + only if unsigned or if dividing by something we know != -1. */ + shorten = (TREE_UNSIGNED (orig_op0) + || (TREE_CODE (op1) == INTEGER_CST + && (TREE_INT_CST_LOW (op1) != -1 + || TREE_INT_CST_HIGH (op1) != -1))); break; case TRUTH_ANDIF_EXPR: |