+bool
+ir_constant::is_basis() const
+{
+ if (!this->type->is_scalar() && !this->type->is_vector())
+ return false;
+
+ if (this->type->is_boolean())
+ return false;
+
+ unsigned ones = 0;
+ for (unsigned c = 0; c < this->type->vector_elements; c++) {
+ switch (this->type->base_type) {
+ case GLSL_TYPE_FLOAT:
+ if (this->value.f[c] == 1.0)
+ ones++;
+ else if (this->value.f[c] != 0.0)
+ return false;
+ break;
+ case GLSL_TYPE_INT:
+ if (this->value.i[c] == 1)
+ ones++;
+ else if (this->value.i[c] != 0)
+ return false;
+ break;
+ case GLSL_TYPE_UINT:
+ if (int(this->value.u[c]) == 1)
+ ones++;
+ else if (int(this->value.u[c]) != 0)
+ return false;
+ break;
+ default:
+ /* The only other base types are structures, arrays, samplers, and
+ * booleans. Samplers cannot be constants, and the others should
+ * have been filtered out above.
+ */
+ assert(!"Should not get here.");
+ return false;
+ }
+ }
+
+ return ones == 1;
+}
+