MIPS: Use PCNT to implement VisitIntegerBitCount() and VisitLongBitCount()

Test: ./testrunner.py --target --optimizing in QEMU
Test: mma test-art-host-gtest
Change-Id: I6ce5bdc86f951094f656c2f81ae8fc836d7a0b5c
diff --git a/compiler/utils/mips64/assembler_mips64.cc b/compiler/utils/mips64/assembler_mips64.cc
index e1b0e75..5a817fa 100644
--- a/compiler/utils/mips64/assembler_mips64.cc
+++ b/compiler/utils/mips64/assembler_mips64.cc
@@ -2279,6 +2279,26 @@
   EmitMsa3R(0x5, 0x3, wt, ws, wd, 0x15);
 }
 
+void Mips64Assembler::PcntB(VectorRegister wd, VectorRegister ws) {
+  CHECK(HasMsa());
+  EmitMsa2R(0xc1, 0x0, ws, wd, 0x1e);
+}
+
+void Mips64Assembler::PcntH(VectorRegister wd, VectorRegister ws) {
+  CHECK(HasMsa());
+  EmitMsa2R(0xc1, 0x1, ws, wd, 0x1e);
+}
+
+void Mips64Assembler::PcntW(VectorRegister wd, VectorRegister ws) {
+  CHECK(HasMsa());
+  EmitMsa2R(0xc1, 0x2, ws, wd, 0x1e);
+}
+
+void Mips64Assembler::PcntD(VectorRegister wd, VectorRegister ws) {
+  CHECK(HasMsa());
+  EmitMsa2R(0xc1, 0x3, ws, wd, 0x1e);
+}
+
 void Mips64Assembler::ReplicateFPToVectorRegister(VectorRegister dst,
                                                   FpuRegister src,
                                                   bool is_double) {