Emit VMLA for multiply-add on ARM

src/arm/simulator-arm.cc

Index: src/arm/simulator-arm.cc
diff --git a/src/arm/simulator-arm.cc b/src/arm/simulator-arm.cc
index bd7f1bdf98083f505bdf4143b03ad39ec23446d1..efbfff200360f2b6e8618cf3d1ae0becf180ac88 100644
--- a/src/arm/simulator-arm.cc
+++ b/src/arm/simulator-arm.cc
@@ -2778,6 +2778,20 @@ void Simulator::DecodeTypeVFP(Instruction* instr) {
       double dm_value = get_double_from_d_register(vm);
       double dd_value = dn_value * dm_value;
       set_d_register_from_double(vd, dd_value);
+    } else if ((instr->Opc1Value() == 0x0) && !(instr->Opc3Value() & 0x1)) {
+      // vmla
+      if (instr->SzValue() != 0x1) {
+        UNREACHABLE();  // Not used by V8.
+      }
+
+      double dd_value = get_double_from_d_register(vd);
+      double dn_value = get_double_from_d_register(vn);
+      double dm_value = get_double_from_d_register(vm);
+
+      // Note: we do the mul and add in separate steps to avoid getting a result
+      // with too high precision.
+      set_d_register_from_double(vd, dn_value * dm_value);
+      set_d_register_from_double(vd, get_double_from_d_register(vd) + dd_value);
     } else if ((instr->Opc1Value() == 0x4) && !(instr->Opc3Value() & 0x1)) {
       // vdiv
       if (instr->SzValue() != 0x1) {