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Revert "glsl: Fix constant-folding for reciprocal expressions"

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This reverts commit b3cf92aa91.

The reverted commit prevented constant-folding of reciprocal expressions
when the reciprocated expression was 0. However, since the spec allows
division by zero, constant-folding *is* permissible in this case.

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.
This commit is contained in:
Chad Versace
2011-02-14 11:16:42 -08:00
parent a231ac23f4
commit f2e9981e43
1 changed files with 6 additions and 10 deletions
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16
src/glsl/ir_constant_expression.cpp
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@@ -288,24 +288,20 @@ ir_expression::constant_expression_value()
break;
case ir_unop_rcp:
/* FINISHME: Emit warning when division-by-zero is detected. */
assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
for (unsigned c = 0; c < op[0]->type->components(); c++) {
switch (this->type->base_type) {
case GLSL_TYPE_UINT:
if (op[0]->value.u[c] == 0.0)
return NULL;
data.u[c] = 1 / op[0]->value.u[c];
if (op[0]->value.u[c] != 0.0)
data.u[c] = 1 / op[0]->value.u[c];
break;
case GLSL_TYPE_INT:
if (op[0]->value.i[c] == 0.0)
return NULL;
data.i[c] = 1 / op[0]->value.i[c];
if (op[0]->value.i[c] != 0.0)
data.i[c] = 1 / op[0]->value.i[c];
break;
case GLSL_TYPE_FLOAT:
if (op[0]->value.f[c] == 0.0)
return NULL;
data.f[c] = 1.0F / op[0]->value.f[c];
if (op[0]->value.f[c] != 0.0)
data.f[c] = 1.0F / op[0]->value.f[c];
break;
default:
assert(0);