glsl: Add conditional-select IR.

It's a ?: that operates per-component on vectors. Will be used in
upcoming lowering pass for ldexp and the implementation of frexp.

 csel(selector, a, b):
   per-component result = selector ? a : b

Reviewed-by: Kenneth Graunke <[email protected]>
Reviewed-by: Ian Romanick <[email protected]>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/glsl/ir_builder.cpp b/src/glsl/ir_builder.cpp
index ba14cf3744b..98b43229508 100644
--- a/src/glsl/ir_builder.cpp
+++ b/src/glsl/ir_builder.cpp
@@ -493,6 +493,12 @@ lrp(operand x, operand y, operand a)
 }
 
 ir_expression *
+csel(operand a, operand b, operand c)
+{
+   return expr(ir_triop_csel, a, b, c);
+}
+
+ir_expression *
 bitfield_insert(operand a, operand b, operand c, operand d)
 {
    void *mem_ctx = ralloc_parent(a.val);