[PowerPC] Fix readcyclecounter to be custom expanded for all 32-bit targets

We need to use the custom expansion of readcyclecounter on all 32-bit targets
(even those with 64-bit registers). This should fix the ppc64 buildbot.

llvm-svn: 223182
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 3668a87..d913f3b 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -599,12 +599,10 @@
     }
   }
 
-  if (Subtarget.has64BitSupport()) {
+  if (Subtarget.has64BitSupport())
     setOperationAction(ISD::PREFETCH, MVT::Other, Legal);
-    setOperationAction(ISD::READCYCLECOUNTER, MVT::i64, Legal);
-  } else {
-    setOperationAction(ISD::READCYCLECOUNTER, MVT::i64, Custom);
-  }
+
+  setOperationAction(ISD::READCYCLECOUNTER, MVT::i64, isPPC64 ? Legal : Custom);
 
   if (!isPPC64) {
     setOperationAction(ISD::ATOMIC_LOAD,  MVT::i64, Expand);