PPC: [Atomics] Remove Atomics code stubs; use TF ops

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 2bf4860d4d7030cb8c7627cb8f176fe2e2400e55..51a8950a84dff355bb2a286a30e179fa6189a4c0 100644
--- a/src/compiler/ppc/code-generator-ppc.cc
+++ b/src/compiler/ppc/code-generator-ppc.cc
@@ -672,6 +672,24 @@ Condition FlagsConditionToCondition(FlagsCondition condition, ArchOpcode op) {
     DCHECK_EQ(LeaveRC, i.OutputRCBit());                      \
   } while (0)
 
+#define ASSEMBLE_ATOMIC_LOAD_INTEGER(asm_instr, asm_instrx)   \
+  do {                                                        \
+    Label done;                                               \
+    Register result = i.OutputRegister();                     \
+    AddressingMode mode = kMode_None;                         \
+    MemOperand operand = i.MemoryOperand(&mode);              \
+    __ sync();                                                \
+    if (mode == kMode_MRI) {                                  \
+    __ asm_instr(result, operand);                            \
+    } else {                                                  \
+    __ asm_instrx(result, operand);                           \
+    }                                                         \
+    __ bind(&done);                                           \
+    __ cmp(result, result);                                   \
+    __ bne(&done);                                            \
+    __ isync();                                               \
+  } while (0)
+
 void CodeGenerator::AssembleDeconstructFrame() {
   __ LeaveFrame(StackFrame::MANUAL);
 }
@@ -1585,6 +1603,23 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
     case kCheckedStoreFloat64:
       ASSEMBLE_CHECKED_STORE_DOUBLE();
       break;
+
+    case kAtomicLoadInt8:
+      ASSEMBLE_ATOMIC_LOAD_INTEGER(lbz, lbzx);
+      __ extsb(i.OutputRegister(), i.OutputRegister());
+      break;
+    case kAtomicLoadUint8:
+      ASSEMBLE_ATOMIC_LOAD_INTEGER(lbz, lbzx);
+      break;
+    case kAtomicLoadInt16:
+      ASSEMBLE_ATOMIC_LOAD_INTEGER(lha, lhax);
+      break;
+    case kAtomicLoadUint16:
+      ASSEMBLE_ATOMIC_LOAD_INTEGER(lhz, lhzx);
+      break;
+    case kAtomicLoadWord32:
+      ASSEMBLE_ATOMIC_LOAD_INTEGER(lwa, lwax);
+      break;
     default:
       UNREACHABLE();
       break;