diff options
| author | Matt Turner <mattst88@gmail.com> | 2018-11-21 12:13:19 -0800 |
|---|---|---|
| committer | Matt Turner <mattst88@gmail.com> | 2018-11-28 11:22:47 -0800 |
| commit | 2d48d5116bfe589804e60bbb8fcb261b7b208949 (patch) | |
| tree | b5781c23006fc4db63cc59f9c60d65aff104feaa | |
| parent | e2ad94d92884d084f726f22c6beca69a36c4569d (diff) | |
gallivm: Use nextafterf(0.5, 0.0) as rounding constant
The common truncf(x + 0.5) fails for the floating-point value just less
than 0.5 (nextafterf(0.5, 0.0)). nextafterf(0.5, 0.0) + 0.5, after
rounding is 1.0, thus truncf does not produce the desired value.
The solution is to add nextafterf(0.5, 0.0) instead of 0.5 before
truncating. This works for all values.
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
| -rw-r--r-- | src/gallium/auxiliary/gallivm/lp_bld_arit.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_arit.c b/src/gallium/auxiliary/gallivm/lp_bld_arit.c index f348833206b..c050bfdb936 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_arit.c +++ b/src/gallium/auxiliary/gallivm/lp_bld_arit.c @@ -2477,7 +2477,7 @@ lp_build_iround(struct lp_build_context *bld, else { LLVMValueRef half; - half = lp_build_const_vec(bld->gallivm, type, 0.5); + half = lp_build_const_vec(bld->gallivm, type, nextafterf(0.5, 0.0)); if (type.sign) { LLVMTypeRef vec_type = bld->vec_type; |