S390: [wasm] Int64Lowering of Int64Sub.

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

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/code-generator.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
@@ skipping 854 matching lines @@
     case kS390_AddPair:
       // i.InputRegister(0) ... left low word.
       // i.InputRegister(1) ... left high word.
       // i.InputRegister(2) ... right low word.
       // i.InputRegister(3) ... right high word.
       __ AddLogical32(i.OutputRegister(0), i.InputRegister(0),
                       i.InputRegister(2));
       __ 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),
                          i.InputRegister(0), i.InputRegister(1),
                          i.InputInt32(2));
       } else {
         __ ShiftLeftPair(i.OutputRegister(0), i.OutputRegister(1),
                          i.InputRegister(0), i.InputRegister(1), kScratchReg,
                          i.InputRegister(2));
       }
@@ skipping 1163 matching lines @@
       padding_size -= 2;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8