S390: Implement Float/Double NearestInt

Flags are also updated under `instruction-selector` to include
these operations. Not having them was causing their Simd versions
to remain unused as well. V8 was just interpreting them at runtime.

Change-Id: I42677f7412859ad4759b70ba16667ec9d90505af
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2994803Reviewed-by: Junliang Yan <junyan@redhat.com>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/master@{#75444}

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

@@ -1794,6 +1794,9 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
       __ FloatMin(i.OutputDoubleRegister(), i.InputDoubleRegister(0),
                   i.InputDoubleRegister(1));
       break;
+    case kS390_FloatNearestInt:
+      __ NearestIntF32(i.OutputDoubleRegister(), i.InputDoubleRegister(0));
+      break;
     case kS390_MinDouble:
       __ DoubleMin(i.OutputDoubleRegister(), i.InputDoubleRegister(0),
                    i.InputDoubleRegister(1));
@@ -1814,6 +1817,9 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
       __ fidbra(ROUND_TO_NEAREST_AWAY_FROM_0, i.OutputDoubleRegister(),
                 i.InputDoubleRegister(0));
       break;
+    case kS390_DoubleNearestInt:
+      __ NearestIntF64(i.OutputDoubleRegister(), i.InputDoubleRegister(0));
+      break;
     case kS390_NegFloat:
       ASSEMBLE_UNARY_OP(D_DInstr(lcebr), nullInstr, nullInstr);
       break;

src/compiler/backend/s390/instruction-codes-s390.h

@@ -69,12 +69,14 @@ namespace compiler {
   V(S390_FloorFloat)                        \
   V(S390_CeilFloat)                         \
   V(S390_TruncateFloat)                     \
+  V(S390_FloatNearestInt)                   \
   V(S390_AbsFloat)                          \
   V(S390_SqrtDouble)                        \
   V(S390_FloorDouble)                       \
   V(S390_CeilDouble)                        \
   V(S390_TruncateDouble)                    \
   V(S390_RoundDouble)                       \
+  V(S390_DoubleNearestInt)                  \
   V(S390_MaxFloat)                          \
   V(S390_MaxDouble)                         \
   V(S390_MinFloat)                          \

src/compiler/backend/s390/instruction-scheduler-s390.cc

@@ -69,12 +69,14 @@ int InstructionScheduler::GetTargetInstructionFlags(
     case kS390_FloorFloat:
     case kS390_CeilFloat:
     case kS390_TruncateFloat:
+    case kS390_FloatNearestInt:
     case kS390_AbsFloat:
     case kS390_SqrtDouble:
     case kS390_FloorDouble:
     case kS390_CeilDouble:
     case kS390_TruncateDouble:
     case kS390_RoundDouble:
+    case kS390_DoubleNearestInt:
     case kS390_MaxFloat:
     case kS390_MaxDouble:
     case kS390_MinFloat:

src/compiler/backend/s390/instruction-selector-s390.cc

@@ -1311,6 +1311,10 @@ static inline bool TryMatchDoubleConstructFromInsert(
     null)                                                                      \
   V(Float64, Float64RoundTiesAway, kS390_RoundDouble, OperandMode::kNone,      \
     null)                                                                      \
+  V(Float32, Float32RoundTiesEven, kS390_FloatNearestInt, OperandMode::kNone,  \
+    null)                                                                      \
+  V(Float64, Float64RoundTiesEven, kS390_DoubleNearestInt, OperandMode::kNone, \
+    null)                                                                      \
   V(Float32, Float32Neg, kS390_NegFloat, OperandMode::kNone, null)             \
   V(Float64, Float64Neg, kS390_NegDouble, OperandMode::kNone, null)            \
   /* TODO(john.yan): can use kAllowRM */                                       \
@@ -1557,14 +1561,6 @@ void InstructionSelector::VisitFloat64Ieee754Binop(Node* node,
       ->MarkAsCall();
 }
 
-void InstructionSelector::VisitFloat32RoundTiesEven(Node* node) {
-  UNREACHABLE();
-}
-
-void InstructionSelector::VisitFloat64RoundTiesEven(Node* node) {
-  UNREACHABLE();
-}
-
 static bool CompareLogical(FlagsContinuation* cont) {
   switch (cont->condition()) {
     case kUnsignedLessThan:
@@ -2875,6 +2871,8 @@ InstructionSelector::SupportedMachineOperatorFlags() {
          MachineOperatorBuilder::kFloat64RoundUp |
          MachineOperatorBuilder::kFloat32RoundTruncate |
          MachineOperatorBuilder::kFloat64RoundTruncate |
+         MachineOperatorBuilder::kFloat32RoundTiesEven |
+         MachineOperatorBuilder::kFloat64RoundTiesEven |
          MachineOperatorBuilder::kFloat64RoundTiesAway |
          MachineOperatorBuilder::kWord32Popcnt |
          MachineOperatorBuilder::kInt32AbsWithOverflow |