[RISCV] Mark C.EBREAK instruction as having side effects

[luismarques]

Summary

C.EBREAK was defined with hasSideEffects = 0, which is incorrect and inconsistent with the non-compressed instruction form. This patch corrects this oversight.

[asb]

Looks good to me. This won't cause any codegen issues because C_EBREAK is never gets selected in ISel anyway (EBREAK will get converted after it becomes an MCInst). But it's better to have the right metadata.

llvm/trunk/lib/Target/RISCV/RISCVInstrInfoC.td

def C_JR : RVInst16CR<0b1000, 0b10, (outs), (ins GPRNoX0:$rs1),
   let isIndirectBranch = 1;
   let rs2 = 0;
 }
 
 let hasSideEffects = 0, mayLoad = 0, mayStore = 0 in
 def C_MV : RVInst16CR<0b1000, 0b10, (outs GPRNoX0:$rs1), (ins GPRNoX0:$rs2),
                       "c.mv", "$rs1, $rs2">;
 
-let rs1 = 0, rs2 = 0, hasSideEffects = 0, mayLoad = 0, mayStore = 0 in
+let rs1 = 0, rs2 = 0, hasSideEffects = 1, mayLoad = 0, mayStore = 0 in
 def C_EBREAK : RVInst16CR<0b1001, 0b10, (outs), (ins), "c.ebreak", "">;
 
 let hasSideEffects = 0, mayLoad = 0, mayStore = 0,
     isCall=1, Defs=[X1], rs2 = 0 in
 def C_JALR : RVInst16CR<0b1001, 0b10, (outs), (ins GPRNoX0:$rs1),
                         "c.jalr", "$rs1">;
 
 let hasSideEffects = 0, mayLoad = 0, mayStore = 0 in