PPC: Fix register corruption

Fix register corruption and save constant pool register.

R=joransiu@ca.ibm.com, jyan@ca.ibm.com
BUG=
LOG=N

Change-Id: I278b7f9a60e10c5347cdfba52432837f68c82836
Reviewed-on: https://chromium-review.googlesource.com/649812
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#47832}

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

@@ -230,6 +230,9 @@ class OutOfLineRecordWrite final : public OutOfLineCode {
         Builtins::CallableFor(__ isolate(), Builtins::kRecordWrite);
     RegList registers = callable.descriptor().allocatable_registers();
 
+    if (FLAG_enable_embedded_constant_pool) {
+      registers |= kConstantPoolRegister.bit();
+    }
     SaveRegisters(registers);
     __ mflr(scratch0_);
     __ Push(scratch0_);
@@ -262,8 +265,8 @@ class OutOfLineRecordWrite final : public OutOfLineCode {
         frame()->DidAllocateDoubleRegisters() ? kSaveFPRegs : kDontSaveFPRegs;
     if (must_save_lr_) {
       // We need to save and restore lr if the frame was elided.
-      __ mflr(scratch1_);
-      __ Push(scratch1_);
+      __ mflr(scratch0_);
+      __ Push(scratch0_);
     }
     if (must_save_lr_ && FLAG_enable_embedded_constant_pool) {
       ConstantPoolUnavailableScope constant_pool_unavailable(tasm());
@@ -277,8 +280,8 @@ class OutOfLineRecordWrite final : public OutOfLineCode {
     }
     if (must_save_lr_) {
       // We need to save and restore lr if the frame was elided.
-      __ Pop(scratch1_);
-      __ mtlr(scratch1_);
+      __ Pop(scratch0_);
+      __ mtlr(scratch0_);
     }
 #endif
   }