glsl: Add ir_binop_vector_extract in NIR

Implement ir_binop_vector_extract using NIR operations. Based on SPIR-V
to NIR approach.

This fixes:
dEQP-GLES3.functional.shaders.indexing.moredynamic.with_value_from_indexing_expression_fragment
Piglit's glsl-fs-vec4-indexing-8.shader_test

CC: [email protected]
Signed-off-by: Juan A. Suarez Romero <[email protected]>

Reviewed-by: Eric Anholt <[email protected]>
Reviewed-by: Iago Toral <[email protected]>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/compiler/glsl/glsl_to_nir.cpp b/src/compiler/glsl/glsl_to_nir.cpp
index dc3e822308b..baaa3affed9 100644
--- a/src/compiler/glsl/glsl_to_nir.cpp
+++ b/src/compiler/glsl/glsl_to_nir.cpp
@@ -1940,6 +1940,15 @@ nir_visitor::visit(ir_expression *ir)
             unreachable("not reached");
       }
       break;
+   case ir_binop_vector_extract: {
+      result = nir_channel(&b, srcs[0], 0);
+      for (unsigned i = 1; i < ir->operands[0]->type->vector_elements; i++) {
+         nir_ssa_def *swizzled = nir_channel(&b, srcs[0], i);
+         result = nir_bcsel(&b, nir_ieq(&b, srcs[1], nir_imm_int(&b, i)),
+                            swizzled, result);
+      }
+      break;
+   }
 
    case ir_binop_ldexp: result = nir_ldexp(&b, srcs[0], srcs[1]); break;
    case ir_triop_fma: