arch-vega: Ignore s_setprio instruction instead of panic (#438)

This instruction is used by ML frameworks to prioritize certain
wavefronts. Since gem5 does not have any support for wavefront
scheduling based on priority (besides wavefront age), we ignore this
instruction and warn_once rather than calling panic. Since hardware can
override this priority anyways, we can be sure that ignoring the value
will not inhibit forward progress resulting in application hangs.

Change-Id: Ic5eef14f9685dd2b316c5cf76078bb78d5bfe3cc

src/arch/amdgpu/vega/insts/instructions.cc

@@ -4728,6 +4728,7 @@ namespace VegaISA
     Inst_SOPP__S_SETPRIO::Inst_SOPP__S_SETPRIO(InFmt_SOPP *iFmt)
         : Inst_SOPP(iFmt, "s_setprio")
     {
+        setFlag(ALU);
     } // Inst_SOPP__S_SETPRIO
 
     Inst_SOPP__S_SETPRIO::~Inst_SOPP__S_SETPRIO()
@@ -4742,7 +4743,10 @@ namespace VegaISA
     void
     Inst_SOPP__S_SETPRIO::execute(GPUDynInstPtr gpuDynInst)
     {
-        panicUnimplemented();
+        ScalarRegU16 simm16 = instData.SIMM16;
+        ScalarRegU32 userPrio = simm16 & 0x3;
+
+        warn_once("S_SETPRIO ignored -- Requested priority %d\n", userPrio);
     } // execute
     // --- Inst_SOPP__S_SENDMSG class methods ---