glsl: Optimize (f2i(trunc x)) into (f2i x).

total instructions in shared programs: 5950326 -> 5949286 (-0.02%)
instructions in affected programs:     88264 -> 87224 (-1.18%)
helped:                                692

1 files changed, 9 insertions, 0 deletions

diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp
index 588228c9ec2..7bc65daf5c6 100644
--- a/src/glsl/opt_algebraic.cpp
+++ b/src/glsl/opt_algebraic.cpp
@@ -376,6 +376,15 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir)
       }
       break;
 
+   case ir_unop_f2i:
+   case ir_unop_f2u:
+      if (op_expr[0] && op_expr[0]->operation == ir_unop_trunc) {
+         return new(mem_ctx) ir_expression(ir->operation,
+                                           ir->type,
+                                           op_expr[0]->operands[0]);
+      }
+      break;
+
    case ir_unop_logic_not: {
       enum ir_expression_operation new_op = ir_unop_logic_not;