[Mesa-dev] [PATCH 07/22] glsl: Add saturate to get_range

[Thomas Helland]

We can use the intersection function to reduce the range
even further if the operand has bounds between 0.0 and 1.0.

v2: Rewrite as suggested by Ian.
    Put in alphabetic order.
---
 src/glsl/opt_minmax.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/glsl/opt_minmax.cpp b/src/glsl/opt_minmax.cpp
index ffdf203..8fee0aa 100644
--- a/src/glsl/opt_minmax.cpp
+++ b/src/glsl/opt_minmax.cpp
@@ -308,6 +308,11 @@ get_range(ir_rvalue *rval)
          low = new(mem_ctx) ir_constant(0.0f);
          return minmax_range(low, high);
 
+      case ir_unop_saturate:
+         r0 = minmax_range(new(mem_ctx) ir_constant(0.0f),
+                           new(mem_ctx) ir_constant(1.0f));
+         return range_intersection(get_range(expr->operands[0]), r0);
+
       case ir_unop_sin:
       case ir_unop_sin_reduced:
       case ir_unop_cos:
-- 
2.2.1