diff options
| author | Chad Versace <chad.versace@intel.com> | 2011-02-14 13:22:39 -0800 |
|---|---|---|
| committer | Ian Romanick <ian.d.romanick@intel.com> | 2011-02-28 14:52:09 -0800 |
| commit | 614eff1fc6046f728d9faced84ffedb15cb601b1 (patch) | |
| tree | 7e33e4bae53ad09d9d3b32fd932d701cd22dca37 | |
| parent | 89576ea75b06681081883f0f9c5a2e0e2d44c837 (diff) | |
glsl: Reinstate constant-folding for division by zero
Fixes regression: https://bugs.freedesktop.org/show_bug.cgi?id=34160
Commit e7c1f058d18f62aa4871aec623f994d7b68cb8c1 disabled constant-folding
when division-by-zero occured. This was a mistake, because the spec does
allow division by zero. (From section 5.9 of the GLSL 1.20 spec: Dividing
by zero does not cause an exception but does result in an unspecified
value.)
For floating-point division, the original pre-e7c1f05 behavior is
reinstated.
For integer division, constant-fold 1/0 to 0.
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
(cherry picked from commit 62c8c773334c1b0cdd484997a4ccec8945713f8c)
| -rw-r--r-- | src/glsl/ir_constant_expression.cpp | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/src/glsl/ir_constant_expression.cpp b/src/glsl/ir_constant_expression.cpp index cf958aa7a17..b5850bea10e 100644 --- a/src/glsl/ir_constant_expression.cpp +++ b/src/glsl/ir_constant_expression.cpp @@ -514,10 +514,18 @@ ir_expression::constant_expression_value() switch (op[0]->type->base_type) { case GLSL_TYPE_UINT: - data.u[c] = op[0]->value.u[c0] / op[1]->value.u[c1]; + if (op[1]->value.u[c1] == 0) { + data.u[c] = 0; + } else { + data.u[c] = op[0]->value.u[c0] / op[1]->value.u[c1]; + } break; case GLSL_TYPE_INT: - data.i[c] = op[0]->value.i[c0] / op[1]->value.i[c1]; + if (op[1]->value.i[c1] == 0) { + data.i[c] = 0; + } else { + data.i[c] = op[0]->value.i[c0] / op[1]->value.i[c1]; + } break; case GLSL_TYPE_FLOAT: data.f[c] = op[0]->value.f[c0] / op[1]->value.f[c1]; @@ -536,10 +544,18 @@ ir_expression::constant_expression_value() switch (op[0]->type->base_type) { case GLSL_TYPE_UINT: - data.u[c] = op[0]->value.u[c0] % op[1]->value.u[c1]; + if (op[1]->value.u[c1] == 0) { + data.u[c] = 0; + } else { + data.u[c] = op[0]->value.u[c0] % op[1]->value.u[c1]; + } break; case GLSL_TYPE_INT: - data.i[c] = op[0]->value.i[c0] % op[1]->value.i[c1]; + if (op[1]->value.i[c1] == 0) { + data.i[c] = 0; + } else { + data.i[c] = op[0]->value.i[c0] % op[1]->value.i[c1]; + } break; case GLSL_TYPE_FLOAT: /* We don't use fmod because it rounds toward zero; GLSL specifies |