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

This reverts commit b3cf92aa916ee0537ee37723c23a9897ac9cd3e0.

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.

diff --git a/src/glsl/ir_constant_expression.cpp b/src/glsl/ir_constant_expression.cpp
index 2841fb3..7e00db6 100644 (file)
--- a/src/glsl/ir_constant_expression.cpp
+++ b/src/glsl/ir_constant_expression.cpp
@@ -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);