[Mesa-dev] [PATCH 1/2] intel/compiler: grf127 can not be dest when src and dest overlap in send

[Jose Maria Casanova Crespo]

Implement at brw_eu_validate the restriction from Intel Broadwell PRM, vol 07,
section "Instruction Set Reference", subsection "EUISA Instructions", Send
Message (page 990):

"r127 must not be used for return address when there is a src and dest overlap
in send instruction."

Cc: Jason Ekstrand <jason at jlekstrand.net>
Cc: Matt Turner <mattst88 at gmail.com>
---
 src/intel/compiler/brw_eu_validate.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/intel/compiler/brw_eu_validate.c b/src/intel/compiler/brw_eu_validate.c
index d3189d1ef5e..0d711501303 100644
--- a/src/intel/compiler/brw_eu_validate.c
+++ b/src/intel/compiler/brw_eu_validate.c
@@ -261,6 +261,15 @@ send_restrictions(const struct gen_device_info *devinfo,
                   brw_inst_src0_da_reg_nr(devinfo, inst) < 112,
                   "send with EOT must use g112-g127");
       }
+      if (devinfo->gen >= 8) {
+         ERROR_IF(!dst_is_null(devinfo, inst) &&
+                  (brw_inst_dst_da_reg_nr(devinfo, inst) +
+                   brw_inst_rlen(devinfo, inst) > 127 ) &&
+                  (brw_inst_src0_da_reg_nr(devinfo, inst) +
+                   brw_inst_mlen(devinfo, inst) >
+                   brw_inst_dst_da_reg_nr(devinfo, inst)),
+                  "r127 can not be dest when src and dest overlap in send");
+      }
    }
 
    return error_msg;
-- 
2.16.3