[Mesa-dev] [PATCH] spirv: convert some operands for bitwise shift and bitwise ops to uint32

[Samuel Iglesias Gonsálvez]

SPIR-V allows to define the shift, offset and count operands for
shift and bitfield opcodes with a bit-size different than 32 bits,
but in NIR the opcodes have that limitation. As agreed in the
mailing list, this patch adds a conversion to 32 bits to fix this.

For more info, see:

https://lists.freedesktop.org/archives/mesa-dev/2018-April/193026.html

Signed-off-by: Samuel Iglesias Gonsálvez <siglesias at igalia.com>
---
 src/compiler/spirv/vtn_alu.c | 47 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/src/compiler/spirv/vtn_alu.c b/src/compiler/spirv/vtn_alu.c
index 3134849ba90..36e5751bc05 100644
--- a/src/compiler/spirv/vtn_alu.c
+++ b/src/compiler/spirv/vtn_alu.c
@@ -635,6 +635,53 @@ vtn_handle_alu(struct vtn_builder *b, SpvOp opcode,
       break;
    }
 
+   case SpvOpBitFieldInsert:
+   case SpvOpBitFieldSExtract:
+   case SpvOpBitFieldUExtract:
+   case SpvOpShiftLeftLogical:
+   case SpvOpShiftRightArithmetic:
+   case SpvOpShiftRightLogical: {
+      bool swap;
+      unsigned initial_source = 0;
+      unsigned src_bit_size = glsl_get_bit_size(vtn_src[0]->type);
+      unsigned dst_bit_size = glsl_get_bit_size(type);
+      nir_op op = vtn_nir_alu_op_for_spirv_opcode(b, opcode, &swap,
+                                                  src_bit_size, dst_bit_size);
+
+      assert (op == nir_op_ushr || op == nir_op_ishr || op == nir_op_ishl ||
+              op == nir_op_bitfield_insert || op == nir_op_ubitfield_extract ||
+              op == nir_op_ibitfield_extract);
+
+      switch (op) {
+      case nir_op_ushr:
+      case nir_op_ishr:
+      case nir_op_ishl:
+      case nir_op_ubitfield_extract:
+      case nir_op_ibitfield_extract:
+         initial_source = 1;
+         break;
+      case nir_op_bitfield_insert:
+         initial_source = 2;
+         break;
+      default:
+         unreachable("Not supported opcode");
+      };
+      for (unsigned i = initial_source; i < nir_op_infos[op].num_inputs; i++) {
+         src_bit_size = nir_alu_type_get_type_size(nir_op_infos[op].input_types[i]);
+         assert(src_bit_size == 32);
+         if (src_bit_size && src_bit_size != src[i]->bit_size) {
+            /* Convert the Shift, Offset and Count  operands to 32 bits, which is the bitsize
+             * supported by the NIR instructions. See discussion here:
+             *
+             * https://lists.freedesktop.org/archives/mesa-dev/2018-April/193026.html
+             */
+            src[i] = nir_u2u32(&b->nb, src[i]);
+         }
+      }
+      val->ssa->def = nir_build_alu(&b->nb, op, src[0], src[1], src[2], src[3]);
+      break;
+   }
+
    default: {
       bool swap;
       unsigned src_bit_size = glsl_get_bit_size(vtn_src[0]->type);
-- 
2.14.1