V2: Add some air for readability
Use the new IS_CONSTANT macro
Combine if-blocks for reduced code-duplication
Split out into separate function for reuse later
V3: Fix flawed logic (Spotted by Bruno)
---
src/glsl/opt_minmax.cpp | 45 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)
diff --git a/src/glsl/opt_minmax.cpp b/src/glsl/opt_minmax.cpp
index 4153a48..373ba26 100644
--- a/src/glsl/opt_minmax.cpp
+++ b/src/glsl/opt_minmax.cpp
@@ -300,6 +300,46 @@ resolv_add_range(minmax_range r0, minmax_range r1)
return minmax_range(low, high);
}
+/* Takes the range of the operands in a mul-operation as parameters
+ * and uses this to solve the range of the mul-operation itself.
+ */
+static minmax_range
+resolv_mul_range(minmax_range r0, minmax_range r1)
+{
+ ir_constant *low = NULL;
+ ir_constant *high = NULL;
+
+ // Both are positive, result is positive
+ if (IS_CONSTANT(r0.low, >=, 0.0f) && IS_CONSTANT(r1.low, >=, 0.0f)) {
+ low = mul(r0.low, r1.low)->constant_expression_value();
+ if (r0.high && r1.high)
+ high = mul(r0.high, r1.high)->constant_expression_value();
+ }
+
+ // Both are negative, result is positive
+ if (IS_CONSTANT(r0.high, <=, 0.0f) && IS_CONSTANT(r1.high, <=, 0.0f)) {
+ low = mul(r0.high, r1.high)->constant_expression_value();
+ if (r0.low && r1.low)
+ high = mul(r0.low, r1.low)->constant_expression_value();
+ }
+
+ // r0 pos and r1 neg, result is negative
+ if (IS_CONSTANT(r0.low, >=, 0.0f) && IS_CONSTANT(r1.high, <=, 0.0f)) {
+ high = mul(r0.low, r1.high)->constant_expression_value();
+ if (r0.high && r1.low)
+ low = mul(r0.high, r1.low)->constant_expression_value();
+ }
+
+ // r0 neg and r1 pos, result is negative
+ if (IS_CONSTANT(r1.low, >=, 0.0f) && IS_CONSTANT(r0.high, <=, 0.0f)) {
+ high = mul(r1.low, r0.high)->constant_expression_value();
+ if (r1.high && r0.low)
+ low = mul(r1.high, r0.low)->constant_expression_value();
+ }
+
+ return minmax_range(low, high);
+}
+
static minmax_range
get_range(ir_rvalue *rval)
{
@@ -389,6 +429,11 @@ get_range(ir_rvalue *rval)
r1 = get_range(expr->operands[1]);
return combine_range(r0, r1, expr->operation == ir_binop_min);
+ case ir_binop_mul:
+ r0 = get_range(expr->operands[0]);
+ r1 = get_range(expr->operands[1]);
+ return resolv_mul_range(r0, r1);
+
default:
break;
}
--
2.2.1
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