spirv: Clean up OpSignBitSet

For some reason, we were doing a signed shift vectors and an unsigned
shift for scalars.  We then plug it into i2b so it should make no
difference whatsoever.  The fact that we're doing different things for
vectors vs. scalars is bonkers.  Let's simplify the code a bit.

Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5278>

diff --git a/src/compiler/spirv/vtn_alu.c b/src/compiler/spirv/vtn_alu.c
index e78f745..611f186 100644 (file)
--- a/src/compiler/spirv/vtn_alu.c
+++ b/src/compiler/spirv/vtn_alu.c
@@ -646,18 +646,10 @@ vtn_handle_alu(struct vtn_builder *b, SpvOp opcode,
       break;
    }
 
-   case SpvOpSignBitSet: {
-      unsigned src_bit_size = glsl_get_bit_size(vtn_src[0]->type);
-      if (src[0]->num_components == 1)
-         val->ssa->def =
-            nir_ushr(&b->nb, src[0], nir_imm_int(&b->nb, src_bit_size - 1));
-      else
-         val->ssa->def =
-            nir_ishr(&b->nb, src[0], nir_imm_int(&b->nb, src_bit_size - 1));
-
-      val->ssa->def = nir_i2b(&b->nb, val->ssa->def);
+   case SpvOpSignBitSet:
+      val->ssa->def = nir_i2b(&b->nb,
+         nir_ushr(&b->nb, src[0], nir_imm_int(&b->nb, src[0]->bit_size - 1)));
       break;
-   }
 
    case SpvOpUCountTrailingZerosINTEL:
       val->ssa->def = nir_umin(&b->nb,