S390: [wasm] Int64Lowering of Int64Sub.

src/compiler/s390/code-generator-s390.cc

Index: src/compiler/s390/code-generator-s390.cc
diff --git a/src/compiler/s390/code-generator-s390.cc b/src/compiler/s390/code-generator-s390.cc
index ffdada286baddaf984f9205835a7fb6091076a41..22ec4e47fac5be057692c1387da29a5b6e737f42 100644
--- a/src/compiler/s390/code-generator-s390.cc
+++ b/src/compiler/s390/code-generator-s390.cc
@@ -872,6 +872,16 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ AddLogicalWithCarry32(i.OutputRegister(1), i.InputRegister(1),
                                i.InputRegister(3));
       break;
+    case kS390_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.
+      __ SubLogical32(i.OutputRegister(0), i.InputRegister(0),
+                      i.InputRegister(2));
+      __ SubLogicalWithBorrow32(i.OutputRegister(1), i.InputRegister(1),
+                                i.InputRegister(3));
+      break;
     case kS390_ShiftLeftPair:
       if (instr->InputAt(2)->IsImmediate()) {
         __ ShiftLeftPair(i.OutputRegister(0), i.OutputRegister(1),