[PowerPC] Implement atomic NAND operations as actual NAND

This changes the implementation of atomic NAND operations
from "a & ~b" (compatible with GCC < 4.4) to actual "~(a & b)"
(compatible with GCC >= 4.4).

This is in line with the common-code and ARM back-end change
implemented in r212433.

llvm-svn: 212547
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index db2003f..bc057bf 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -6833,13 +6833,13 @@
     BB = EmitAtomicBinary(MI, BB, true, PPC::XOR8);
 
   else if (MI->getOpcode() == PPC::ATOMIC_LOAD_NAND_I8)
-    BB = EmitPartwordAtomicBinary(MI, BB, true, PPC::ANDC);
+    BB = EmitPartwordAtomicBinary(MI, BB, true, PPC::NAND);
   else if (MI->getOpcode() == PPC::ATOMIC_LOAD_NAND_I16)
-    BB = EmitPartwordAtomicBinary(MI, BB, false, PPC::ANDC);
+    BB = EmitPartwordAtomicBinary(MI, BB, false, PPC::NAND);
   else if (MI->getOpcode() == PPC::ATOMIC_LOAD_NAND_I32)
-    BB = EmitAtomicBinary(MI, BB, false, PPC::ANDC);
+    BB = EmitAtomicBinary(MI, BB, false, PPC::NAND);
   else if (MI->getOpcode() == PPC::ATOMIC_LOAD_NAND_I64)
-    BB = EmitAtomicBinary(MI, BB, true, PPC::ANDC8);
+    BB = EmitAtomicBinary(MI, BB, true, PPC::NAND8);
 
   else if (MI->getOpcode() == PPC::ATOMIC_LOAD_SUB_I8)
     BB = EmitPartwordAtomicBinary(MI, BB, true, PPC::SUBF);