PPC/s390: [turbofan] Introduce Float64Pow and NumberPow operators.

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

Index: src/compiler/ppc/code-generator-ppc.cc
diff --git a/src/compiler/ppc/code-generator-ppc.cc b/src/compiler/ppc/code-generator-ppc.cc
index 490941409897e18726bf6ea7ea1b1e6578054053..a45d3633d91fcf484916ef45c7a4eb0b20cda289 100644
--- a/src/compiler/ppc/code-generator-ppc.cc
+++ b/src/compiler/ppc/code-generator-ppc.cc
@@ -1301,6 +1301,12 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
     case kIeee754Float64Log10:
       ASSEMBLE_IEEE754_UNOP(log10);
       break;
+    case kIeee754Float64Pow: {
+      MathPowStub stub(isolate(), MathPowStub::DOUBLE);
+      __ CallStub(&stub);
+      __ Move(d1, d3);
+      break;
+    }
     case kPPC_Neg:
       __ neg(i.OutputRegister(), i.InputRegister(0), LeaveOE, i.OutputRCBit());
       break;