[RISCV] Add alias for HFENCE.VVMA

[tangxingxin1008]

Summary

Signed-off-by: Eric Tang <[e-mail]>

[tangxingxin1008]

I don't find explicit alias of these instructions(sfence.vma, hfence.gvma, hfence.vvma) from the Privileged spec, but there is a case about hfence.gvma from linux kvm : https://github.com/torvalds/linux/blob/master/arch/riscv/kvm/tlb.S. According to Privileged spec , "HFENCE.VVMA and HFENCE.GVMA,perform a function similar to SFENCE.VMA (Section 4.2.1)", so add alias for hfence.vvma is a necessary.

[craig.topper]

LGTM. Thanks!

llvm/lib/Target/RISCV/RISCVInstrInfo.td

 }
 
 def : InstAlias<"sfence.vma",     (SFENCE_VMA      X0, X0)>;
 def : InstAlias<"sfence.vma $rs", (SFENCE_VMA GPR:$rs, X0)>;
 
 def : InstAlias<"hfence.gvma",     (HFENCE_GVMA      X0, X0)>;
 def : InstAlias<"hfence.gvma $rs", (HFENCE_GVMA GPR:$rs, X0)>;
 
+def : InstAlias<"hfence.vvma",     (HFENCE_VVMA      X0, X0)>;
+def : InstAlias<"hfence.vvma $rs", (HFENCE_VVMA GPR:$rs, X0)>;
+
 let EmitPriority = 0 in {
 def : InstAlias<"lb $rd, (${rs1})",
                 (LB  GPR:$rd, GPR:$rs1, 0)>;
 def : InstAlias<"lh $rd, (${rs1})",
                 (LH  GPR:$rd, GPR:$rs1, 0)>;
 def : InstAlias<"lw $rd, (${rs1})",
                 (LW  GPR:$rd, GPR:$rs1, 0)>;
 def : InstAlias<"lbu $rd, (${rs1})",

llvm/test/MC/RISCV/rvi-aliases-valid.s

 # CHECK-S-OBJ: sfence.vma a0
 sfence.vma a0
 # CHECK-S-OBJ-NOALIAS: hfence.gvma zero, zero
 # CHECK-S-OBJ: hfence.gvma
 hfence.gvma
 # CHECK-S-OBJ-NOALIAS: hfence.gvma a0, zero
 # CHECK-S-OBJ: hfence.gvma a0
 hfence.gvma a0
+# CHECK-S-OBJ-NOALIAS: hfence.vvma zero, zero
+# CHECK-S-OBJ: hfence.vvma
+hfence.vvma
+# CHECK-S-OBJ-NOALIAS: hfence.vvma a0, zero
+# CHECK-S-OBJ: hfence.vvma a0
+hfence.vvma a0
 
 # The following aliases are accepted as input but the canonical form
 # of the instruction will always be printed.
 # CHECK-S-OBJ-NOALIAS: addi a2, a3, 4
 # CHECK-S-OBJ: addi a2, a3, 4
 add a2, a3, 4
 # CHECK-S-OBJ-NOALIAS: andi a2, a3, 4
 # CHECK-S-OBJ: andi a2, a3, 4