opt_algebraic was translating lrp(x, 0, a) into add(x, -mul(x, a)).
Unfortunately, this references "x" twice, which is invalid in the IR,
leading to assertion failures in the validator.
Normally, cloning IR solves this. However, "x" could actually be an
arbitrary expression tree, so copying it could result in huge piles
of wasted computation. This is why we avoid reusing subexpressions.
Instead, transform it into mul(x, add(1.0, -a)), which is equivalent
but doesn't need two references to "x".
Fixes a regression since d5fa8a95621169, which isn't in any stable
branches. Fixes 18 shaders in shader-db (bastion and yofrankie).
Signed-off-by: Kenneth Graunke <kenn...@whitecape.org>
---
src/glsl/opt_algebraic.cpp | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
Here's the shader-db output comparing master to this:
GAINED: shaders/bastion/48.shader_test fs16
GAINED: shaders/bastion/48.shader_test fs8
GAINED: shaders/bastion/48.shader_test vs
GAINED: shaders/yofrankie/27.shader_test fs16
GAINED: shaders/yofrankie/27.shader_test fs8
GAINED: shaders/yofrankie/27.shader_test vs
GAINED: shaders/yofrankie/30.shader_test fs16
GAINED: shaders/yofrankie/30.shader_test fs8
GAINED: shaders/yofrankie/30.shader_test vs
GAINED: shaders/yofrankie/48.shader_test fs16
GAINED: shaders/yofrankie/48.shader_test fs8
GAINED: shaders/yofrankie/48.shader_test vs
GAINED: shaders/yofrankie/87.shader_test fs16
GAINED: shaders/yofrankie/87.shader_test fs8
GAINED: shaders/yofrankie/87.shader_test vs
GAINED: shaders/yofrankie/9.shader_test fs16
GAINED: shaders/yofrankie/9.shader_test fs8
GAINED: shaders/yofrankie/9.shader_test vs
total instructions in shared programs: 1726391 -> 1726391 (0.00%)
instructions in affected programs: 0 -> 0
GAINED: 18
LOST:
diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp
index 778638c..5c49a78 100644
--- a/src/glsl/opt_algebraic.cpp
+++ b/src/glsl/opt_algebraic.cpp
@@ -571,7 +571,9 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir)
} else if (is_vec_zero(op_const[0])) {
return mul(ir->operands[1], ir->operands[2]);
} else if (is_vec_zero(op_const[1])) {
- return add(ir->operands[0], neg(mul(ir->operands[0],
ir->operands[2])));
+ unsigned op2_components = ir->operands[2]->type->vector_elements;
+ ir_constant *one = new(mem_ctx) ir_constant(1.0f, op2_components);
+ return mul(ir->operands[0], add(one, neg(ir->operands[2])));
}
break;
--
1.9.0
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