Use const qualifiers with TargetLowering. This eliminates several
const_casts, and it reinforces the design of the Target classes being
immutable.

SelectionDAGISel::IsLegalToFold is now a static member function, because
PIC16 uses it in an unconventional way. There is more room for API
cleanup here.

And PIC16's AsmPrinter no longer uses TargetLowering.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101635 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86TargetMachine.h b/lib/Target/X86/X86TargetMachine.h
index ae7b5b2..dc4234c 100644
--- a/lib/Target/X86/X86TargetMachine.h
+++ b/lib/Target/X86/X86TargetMachine.h
@@ -51,8 +51,8 @@
   virtual const TargetFrameInfo  *getFrameInfo() const { return &FrameInfo; }
   virtual       X86JITInfo       *getJITInfo()         { return &JITInfo; }
   virtual const X86Subtarget     *getSubtargetImpl() const{ return &Subtarget; }
-  virtual       X86TargetLowering *getTargetLowering() const { 
-    return const_cast<X86TargetLowering*>(&TLInfo); 
+  virtual const X86TargetLowering *getTargetLowering() const { 
+    return &TLInfo;
   }
   virtual const X86RegisterInfo  *getRegisterInfo() const {
     return &InstrInfo.getRegisterInfo();