i965/fs: Detect multi-register MOVs correctly in register_coalesce.

register_coalesce() was considering the exec_size of the MOV
instruction alone to decide whether the register at offset+1 of the
source VGRF was being copied to inst->dst.reg_offset+1 of the
destination VGRF, which is only a valid assumption if the move has a
32-bit execution type.  Use regs_read() instead to find out the number
of registers copied by the instruction.

Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>

diff --git a/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp b/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp
index a253c81..4f00b7f 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp
@@ -195,7 +195,7 @@ fs_visitor::register_coalesce()
             continue;
          }
          reg_to_offset[offset] = inst->dst.reg_offset;
-         if (inst->exec_size == 16)
+         if (inst->regs_written > 1)
             reg_to_offset[offset + 1] = inst->dst.reg_offset + 1;
          mov[offset] = inst;
          channels_remaining -= inst->regs_written;