[PowerPC] Disable shrink wrapping

Shrink wrapping is causing a self-hosting failure on PPC64/Linux. Disable for
now until the problem can be fixed.

llvm-svn: 248924
diff --git a/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp b/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
index b017708..6d9071059 100644
--- a/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
@@ -1710,6 +1710,6 @@
 }
 
 bool PPCFrameLowering::enableShrinkWrapping(const MachineFunction &MF) const {
-  return (MF.getSubtarget<PPCSubtarget>().isSVR4ABI() &&
-          MF.getSubtarget<PPCSubtarget>().isPPC64());
+  // FIXME: Enable this for non-Darwin PPC64 once it is confirmed working.
+  return false;
 }