From 540a17bcd30abc3f14d1e1b0ef81a23fde0ca18d Mon Sep 17 00:00:00 2001
From: Milad Fa <mfarazma@redhat.com>
Date: Wed, 10 May 2023 19:40:36 +0000
Subject: [PATCH] Fix usage of MulHighS64 on <= z13

Change-Id: If7ac06eef57cc3db059c2640b77c80de3b16fced
https://chromium-review.googlesource.com/c/v8/v8/+/4521297

---

Index: node-v20.1.0/deps/v8/src/compiler/backend/s390/code-generator-s390.cc
===================================================================
--- node-v20.1.0.orig/deps/v8/src/compiler/backend/s390/code-generator-s390.cc
+++ node-v20.1.0/deps/v8/src/compiler/backend/s390/code-generator-s390.cc
@@ -1699,15 +1699,18 @@ CodeGenerator::CodeGenResult CodeGenerat
     case kS390_Mul64WithOverflow: {
       Register dst = i.OutputRegister(), src1 = i.InputRegister(0),
                src2 = i.InputRegister(1);
-      DCHECK(!AreAliased(dst, src1, src2));
+      CHECK(!AreAliased(dst, src1, src2));
       if (CpuFeatures::IsSupported(MISC_INSTR_EXT2)) {
         __ msgrkc(dst, src1, src2);
       } else {
-        __ mgrk(r0, src1, src2);  // r0 = high 64-bits, r1 = low 64-bits.
-        __ lgr(dst, r1);
-        __ ShiftRightS64(r1, r1, Operand(63));
+        // Mul high.
+        __ MulHighS64(r1, src1, src2);
+        // Mul low.
+        __ mov(dst, src1);
+        __ MulS64(dst, src2);
         // Test whether {high} is a sign-extension of {result}.
-        __ CmpU64(r0, r1);
+        __ ShiftRightS64(r0, dst, Operand(63));
+        __ CmpU64(r1, r0);
       }
       break;
     }
@@ -1725,20 +1728,7 @@ CodeGenerator::CodeGenResult CodeGenerat
       ASSEMBLE_BIN_OP(RRRInstr(MulHighU64), nullInstr, nullInstr);
       break;
     case kS390_MulHighS64:
-      if (CpuFeatures::IsSupported(MISC_INSTR_EXT2)) {
-        ASSEMBLE_BIN_OP(RRRInstr(MulHighS64), nullInstr, nullInstr);
-      } else {
-        __ Push(r2, r3, i.InputRegister(0), i.InputRegister(1));
-        __ Pop(r2, r3);
-        {
-          FrameScope scope(masm(), StackFrame::INTERNAL);
-          __ PrepareCallCFunction(2, 0, kScratchReg);
-          __ CallCFunction(ExternalReference::int64_mul_high_function(), 2, 0);
-        }
-        __ mov(kScratchReg, r2);
-        __ Pop(r2, r3);
-        __ mov(i.OutputRegister(), kScratchReg);
-      }
+      ASSEMBLE_BIN_OP(RRRInstr(MulHighS64), nullInstr, nullInstr);
       break;
     case kS390_MulFloat:
       ASSEMBLE_BIN_OP(DDInstr(meebr), DMTInstr(MulFloat32), nullInstr);
Index: node-v20.1.0/deps/v8/src/codegen/s390/macro-assembler-s390.cc
===================================================================
--- node-v20.1.0.orig/deps/v8/src/codegen/s390/macro-assembler-s390.cc
+++ node-v20.1.0/deps/v8/src/codegen/s390/macro-assembler-s390.cc
@@ -2906,8 +2906,23 @@ void MacroAssembler::MulS64(Register dst
 }
 
 void MacroAssembler::MulHighS64(Register dst, Register src1, Register src2) {
-  mgrk(r0, src1, src2);
-  lgr(dst, r0);
+  if (CpuFeatures::IsSupported(MISC_INSTR_EXT2)) {
+    mgrk(r0, src1, src2);
+    lgr(dst, r0);
+  } else {
+    SaveFPRegsMode fp_mode = SaveFPRegsMode::kSave;
+    PushCallerSaved(fp_mode, ip);
+    Push(src1, src2);
+    Pop(r2, r3);
+    {
+      FrameScope scope(this, StackFrame::INTERNAL);
+      PrepareCallCFunction(2, 0, r0);
+      CallCFunction(ExternalReference::int64_mul_high_function(), 2, 0);
+    }
+    mov(r0, r2);
+    PopCallerSaved(fp_mode, ip);
+    mov(dst, r0);
+  }
 }
 
 void MacroAssembler::MulHighS64(Register dst, Register src1,