[Mesa-dev] [PATCH 5/6] glsl: Add saturate to get_range

[Thomas Helland]

Also, if the operand has bounds between 0.0 and 1.0
then copy that range up.

Signed-off-by: Thomas Helland <thomashelland90 at gmail.com>
---
 src/glsl/opt_minmax.cpp | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/glsl/opt_minmax.cpp b/src/glsl/opt_minmax.cpp
index 0b9ddc2..4088c80 100644
--- a/src/glsl/opt_minmax.cpp
+++ b/src/glsl/opt_minmax.cpp
@@ -293,6 +293,20 @@ get_range(ir_rvalue *rval)
          low = new(mem_ctx) ir_constant(-1.0f);
          return minmax_range(low, high);
 
+      case ir_unop_saturate:
+         high = new(mem_ctx) ir_constant(1.0f);
+         low = new(mem_ctx) ir_constant(0.0f);
+         r0 = get_range(expr->operands[0]);
+         // Operand has lower bounds between 0.0 - 1.0 gives us new lower bounds
+         if (r0.low && compare_components(r0.low, low) > EQUAL &&
+                       compare_components(r0.low, high) < EQUAL)
+            low = r0.low;
+         // Operand has upper bounds between 0.0 - 1.0 gives us new lower bounds
+         if (r0.high && compare_components(r0.high, low) > EQUAL &&
+                        compare_components(r0.high, high) < EQUAL)
+            high = r0.high;
+         return minmax_range(low, high);
+
       default:
          break;
       }
-- 
2.0.3