PPC: [wasm] Int64Lowering of Int64Sub.

src/compiler/ppc/code-generator-ppc.cc

Index: src/compiler/ppc/code-generator-ppc.cc
diff --git a/src/compiler/ppc/code-generator-ppc.cc b/src/compiler/ppc/code-generator-ppc.cc
index ba7aae69bd55007de56bf8d78955fff861ee4f00..2dfc5747a5f635a0a5a806195d66434c4a11fd6c 100644
--- a/src/compiler/ppc/code-generator-ppc.cc
+++ b/src/compiler/ppc/code-generator-ppc.cc
@@ -978,6 +978,15 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ adde(i.OutputRegister(1), i.InputRegister(1), i.InputRegister(3));
       DCHECK_EQ(LeaveRC, i.OutputRCBit());
       break;
+    case kPPC_SubPair:
+      // i.InputRegister(0) ... left low word.
+      // i.InputRegister(1) ... left high word.
+      // i.InputRegister(2) ... right low word.
+      // i.InputRegister(3) ... right high word.
+      __ subc(i.OutputRegister(0), i.InputRegister(0), i.InputRegister(2));
+      __ sube(i.OutputRegister(1), i.InputRegister(1), i.InputRegister(3));
+      DCHECK_EQ(LeaveRC, i.OutputRCBit());
+      break;
     case kPPC_ShiftLeftPair:
       if (instr->InputAt(2)->IsImmediate()) {
         __ ShiftLeftPair(i.OutputRegister(0), i.OutputRegister(1),