intel/compiler: fix isign for 16-bit integers

We need to use 16-bit constants with 16-bit instructions,
otherwise we get the following validation error:

"Destination stride must be equal to the ratio of the sizes of
 the execution data type to the destination type"

Because the execution data type is 4B due to the 32-bit integer
constant.

Reviewed-by: Jason Ekstrand <[email protected]>

1 files changed, 12 insertions, 5 deletions

diff --git a/src/intel/compiler/brw_fs_nir.cpp b/src/intel/compiler/brw_fs_nir.cpp
index 02aaf144019..db120efab80 100644
--- a/src/intel/compiler/brw_fs_nir.cpp
+++ b/src/intel/compiler/brw_fs_nir.cpp
@@ -865,17 +865,24 @@ fs_visitor::nir_emit_alu(const fs_builder &bld, nir_alu_instr *instr)
       break;
    }
 
-   case nir_op_isign:
+   case nir_op_isign: {
       /*  ASR(val, 31) -> negative val generates 0xffffffff (signed -1).
        *               -> non-negative val generates 0x00000000.
        *  Predicated OR sets 1 if val is positive.
        */
-      assert(nir_dest_bit_size(instr->dest.dest) < 64);
-      bld.CMP(bld.null_reg_d(), op[0], brw_imm_d(0), BRW_CONDITIONAL_G);
-      bld.ASR(result, op[0], brw_imm_d(31));
-      inst = bld.OR(result, result, brw_imm_d(1));
+      uint32_t bit_size = nir_dest_bit_size(instr->dest.dest);
+      assert(bit_size == 32 || bit_size == 16);
+
+      fs_reg zero = bit_size == 32 ? brw_imm_d(0) : brw_imm_w(0);
+      fs_reg one = bit_size == 32 ? brw_imm_d(1) : brw_imm_w(1);
+      fs_reg shift = bit_size == 32 ? brw_imm_d(31) : brw_imm_w(15);
+
+      bld.CMP(bld.null_reg_d(), op[0], zero, BRW_CONDITIONAL_G);
+      bld.ASR(result, op[0], shift);
+      inst = bld.OR(result, result, one);
       inst->predicate = BRW_PREDICATE_NORMAL;
       break;
+   }
 
    case nir_op_frcp:
       inst = bld.emit(SHADER_OPCODE_RCP, result, op[0]);