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glsl2: Fix ir_div_to_mul_rcp for integer division.

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rcp of an integer value did not produce the result you're looking for.
Instead, do the a * rcp(b) as float and truncate after.  This mostly
fixes glsl-fs-loop-nested.
This commit is contained in:
Eric Anholt 2010-07-07 12:25:22 -07:00
parent 43b5b03d67
commit 9cbd8a1d5a
1 changed files with 47 additions and 9 deletions
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56
src/glsl/ir_div_to_mul_rcp.cpp
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@ -33,6 +33,7 @@
*/
#include "ir.h"
#include "glsl_types.h"
class ir_div_to_mul_rcp_visitor : public ir_hierarchical_visitor {
public:
@ -61,16 +62,53 @@ ir_div_to_mul_rcp_visitor::visit_leave(ir_expression *ir)
if (ir->operation != ir_binop_div)
return visit_continue;
/* New expression for the 1.0 / op1 */
ir_rvalue *expr;
expr = new(ir) ir_expression(ir_unop_rcp,
ir->operands[1]->type,
ir->operands[1],
NULL);
if (ir->operands[1]->type->base_type != GLSL_TYPE_INT &&
ir->operands[1]->type->base_type != GLSL_TYPE_UINT) {
/* New expression for the 1.0 / op1 */
ir_rvalue *expr;
expr = new(ir) ir_expression(ir_unop_rcp,
ir->operands[1]->type,
ir->operands[1],
NULL);
/* op0 / op1 -> op0 * (1.0 / op1) */
ir->operation = ir_binop_mul;
ir->operands[1] = expr;
} else {
/* Be careful with integer division -- we need to do it as a
* float and re-truncate, since rcp(n > 1) of an integer would
* just be 0.
*/
ir_rvalue *op0, *op1;
const struct glsl_type *vec_type;
vec_type = glsl_type::get_instance(GLSL_TYPE_FLOAT,
ir->operands[1]->type->vector_elements,
ir->operands[1]->type->matrix_columns);
if (ir->operands[1]->type->base_type == GLSL_TYPE_INT)
op1 = new(ir) ir_expression(ir_unop_i2f, vec_type, ir->operands[1], NULL);
else
op1 = new(ir) ir_expression(ir_unop_u2f, vec_type, ir->operands[1], NULL);
op1 = new(ir) ir_expression(ir_unop_rcp, op1->type, op1, NULL);
vec_type = glsl_type::get_instance(GLSL_TYPE_FLOAT,
ir->operands[0]->type->vector_elements,
ir->operands[0]->type->matrix_columns);
if (ir->operands[0]->type->base_type == GLSL_TYPE_INT)
op0 = new(ir) ir_expression(ir_unop_i2f, vec_type, ir->operands[0], NULL);
else
op0 = new(ir) ir_expression(ir_unop_u2f, vec_type, ir->operands[0], NULL);
op0 = new(ir) ir_expression(ir_binop_mul, vec_type, op0, op1);
ir->operation = ir_unop_f2i;
ir->operands[0] = op0;
ir->operands[1] = NULL;
}
/* op0 / op1 -> op0 * (1.0 / op1) */
ir->operation = ir_binop_mul;
ir->operands[1] = expr;
this->made_progress = true;
return visit_continue;