Enabled frame pointer elimination by default, for llc (#1324)

* Enabled frame pointer elimination by default, for llc

A few saved registers thus can be used for SGPR spill.

* Removed "-O2" from default argument list of KMOPTLLC becasue it
will be anyways overwritten by "-O3" in HCC_OPT later.

Change-Id: Ifc40f6190122f042e999a29c3c6831c509f079ed

lib/clamp-device.in

@@ -28,8 +28,9 @@ KMOPTOPT="${KMOPTOPT:="-O3"}"
 
 # pass extra options to LLC
 # KMOPTLLC can be used to pass last-minute options to llc in the backend
-# if not set, then "-O2" will be passed to llc
-KMOPTLLC="${KMOPTLLC:="-O2"}"
+# add "--frame-pointer=none" as deafult option to llc to enable frame
+# pointer elimination, so saved registers can be used for SGPR spill
+KMOPTLLC="${KMOPTLLC:="--frame-pointer=none"}"
 
 # enable LLVM hijacking
 KMHACKLLVM="${KMHACKLLVM:=0}"