S390: Fix Div64 sequence + DLGR simulation

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 1089 matching lines @@
       if (i.OutputDoubleRegister().is(i.InputDoubleRegister(1))) {
         ASSEMBLE_FLOAT_UNOP(mdbr);
       } else {
         if (!i.OutputDoubleRegister().is(i.InputDoubleRegister(0)))
           __ ldr(i.OutputDoubleRegister(), i.InputDoubleRegister(0));
         __ mdbr(i.OutputDoubleRegister(), i.InputDoubleRegister(1));
       }
       break;
 #if V8_TARGET_ARCH_S390X
     case kS390_Div64:
+      __ LoadRR(r1, i.InputRegister(0));
+      __ dsgr(r0, i.InputRegister(1));  // R1: Dividend
+      __ ltgr(i.OutputRegister(), r1);  // Copy R1: Quotient to output
+      break;
 #endif
     case kS390_Div32:
       __ LoadRR(r0, i.InputRegister(0));
       __ srda(r0, Operand(32));
       __ dr(r0, i.InputRegister(1));
       __ ltr(i.OutputRegister(), r1);
       break;
 #if V8_TARGET_ARCH_S390X
     case kS390_DivU64:
       __ LoadRR(r1, i.InputRegister(0));
       __ LoadImmP(r0, Operand::Zero());
-      __ dlgr(r0, i.InputRegister(1));  // R0:R1 = R1 / divisor -
-      __ ltgr(i.OutputRegister(), r1);  // Copy remainder to output reg
+      __ dlgr(r0, i.InputRegister(1));  // R0:R1: Dividend
+      __ ltgr(i.OutputRegister(), r1);  // Copy R1: Quotient to output
       break;
 #endif
     case kS390_DivU32:
       __ LoadRR(r0, i.InputRegister(0));
       __ srdl(r0, Operand(32));
-      __ dlr(r0, i.InputRegister(1));  // R0:R1 = R1 / divisor -
-      __ ltr(i.OutputRegister(), r1);  // Copy remainder to output reg
+      __ dlr(r0, i.InputRegister(1));  // R0:R1: Dividend
+      __ ltr(i.OutputRegister(), r1);  // Copy R1: Quotient to output
       break;
 
     case kS390_DivFloat:
       // InputDoubleRegister(1)=InputDoubleRegister(0)/InputDoubleRegister(1)
       if (i.OutputDoubleRegister().is(i.InputDoubleRegister(1))) {
         __ ldr(kScratchDoubleReg, i.InputDoubleRegister(1));
         __ ldr(i.OutputDoubleRegister(), i.InputDoubleRegister(0));
         __ debr(i.OutputDoubleRegister(), kScratchDoubleReg);
       } else {
         if (!i.OutputDoubleRegister().is(i.InputDoubleRegister(0)))
@@ skipping 918 matching lines @@
       padding_size -= 2;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8