intel/compiler: Implement untyped atomic float min, max, and compare-swap dataport messages

v2: Split changes to the message type field to another patch.  Suggested
by Caio.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>

src/intel/compiler/brw_fs_generator.cpp

@@ -2196,6 +2196,13 @@ fs_generator::generate_code(const cfg_t *cfg, int dispatch_width)
                             inst->header_size);
          break;
 
+      case SHADER_OPCODE_UNTYPED_ATOMIC_FLOAT:
+         assert(src[2].file == BRW_IMMEDIATE_VALUE);
+         brw_untyped_atomic_float(p, dst, src[0], src[1], src[2].ud,
+                                  inst->mlen, !inst->dst.is_null(),
+                                  inst->header_size);
+         break;
+
       case SHADER_OPCODE_UNTYPED_SURFACE_READ:
          assert(!inst->header_size);
          assert(src[2].file == BRW_IMMEDIATE_VALUE);