i965/fs: rename lower_d2x to lower_conversions

v2:
- Change the name to lower_conversions.

Signed-off-by: Samuel Iglesias Gonsálvez <[email protected]>
Reviewed-by: Francisco Jerez <[email protected]>

1 files changed, 107 insertions, 0 deletions

diff --git a/src/intel/compiler/brw_fs_lower_conversions.cpp b/src/intel/compiler/brw_fs_lower_conversions.cpp
new file mode 100644
index 00000000000..663c9674c49
--- /dev/null
+++ b/src/intel/compiler/brw_fs_lower_conversions.cpp
@@ -0,0 +1,107 @@
+/*
+ * Copyright © 2015 Connor Abbott
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "brw_fs.h"
+#include "brw_cfg.h"
+#include "brw_fs_builder.h"
+
+using namespace brw;
+
+static bool
+supports_type_conversion(const fs_inst *inst) {
+   switch (inst->opcode) {
+   case BRW_OPCODE_MOV:
+   case SHADER_OPCODE_MOV_INDIRECT:
+      return true;
+   case BRW_OPCODE_SEL:
+      return inst->dst.type == get_exec_type(inst);
+   default:
+      /* FIXME: We assume the opcodes don't explicitly mentioned
+       * before just work fine with arbitrary conversions.
+       */
+      return true;
+   }
+}
+
+bool
+fs_visitor::lower_conversions()
+{
+   bool progress = false;
+
+   foreach_block_and_inst(block, fs_inst, inst, cfg) {
+      const fs_builder ibld(this, block, inst);
+      fs_reg dst = inst->dst;
+      bool saturate = inst->saturate;
+
+      if (supports_type_conversion(inst)) {
+         if (get_exec_type_size(inst) == 8 && type_sz(inst->dst.type) < 8) {
+            /* From the Broadwell PRM, 3D Media GPGPU, "Double Precision Float to
+             * Single Precision Float":
+             *
+             *    The upper Dword of every Qword will be written with undefined
+             *    value when converting DF to F.
+             *
+             * So we need to allocate a temporary that's two registers, and then do
+             * a strided MOV to get the lower DWord of every Qword that has the
+             * result.
+             */
+            fs_reg temp = ibld.vgrf(get_exec_type(inst));
+            fs_reg strided_temp = subscript(temp, dst.type, 0);
+
+            assert(inst->size_written == inst->dst.component_size(inst->exec_size));
+            inst->dst = strided_temp;
+            inst->saturate = false;
+            /* As it is an strided destination, we write n-times more being n the
+             * size ratio between source and destination types. Update
+             * size_written accordingly.
+             */
+            inst->size_written = inst->dst.component_size(inst->exec_size);
+            ibld.at(block, inst->next).MOV(dst, strided_temp)->saturate = saturate;
+
+            progress = true;
+         }
+      } else {
+         fs_reg temp0 = ibld.vgrf(get_exec_type(inst));
+
+         assert(inst->size_written == inst->dst.component_size(inst->exec_size));
+         inst->dst = temp0;
+         /* As it is an strided destination, we write n-times more being n the
+          * size ratio between source and destination types. Update
+          * size_written accordingly.
+          */
+         inst->size_written = inst->dst.component_size(inst->exec_size);
+         inst->saturate = false;
+         /* Now, do the conversion to original destination's type. In next iteration,
+          * we will lower it if it is a d2f conversion.
+          */
+         ibld.at(block, inst->next).MOV(dst, temp0)->saturate = saturate;
+
+         progress = true;
+      }
+   }
+
+   if (progress)
+      invalidate_live_intervals();
+
+   return progress;
+}