[llvm] r177120 - Add a new method which enables one to change register classes.

[Reed Kotler]

Author: rkotler
Date: Thu Mar 14 17:02:09 2013
New Revision: 177120

URL: http://llvm.org/viewvc/llvm-project?rev=177120&view=rev
Log:
Add a new method which enables one to change register classes.
See the Mips16ISetLowering.cpp patch to see a use of this.
For now now the extra code in Mips16ISetLowering.cpp is a nop but is
used for test purposes. Mips32 registers are setup and then removed and
then the Mips16 registers are setup. 

Normally you need to add register classes and then call
computeRegisterProperties.


Modified:
    llvm/trunk/include/llvm/Target/TargetLowering.h
    llvm/trunk/lib/Target/Mips/Mips16ISelLowering.cpp

Modified: llvm/trunk/include/llvm/Target/TargetLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetLowering.h?rev=177120&r1=177119&r2=177120&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Target/TargetLowering.h (original)
+++ llvm/trunk/include/llvm/Target/TargetLowering.h Thu Mar 14 17:02:09 2013
@@ -958,6 +958,13 @@ protected:
     RegClassForVT[VT.SimpleTy] = RC;
   }
 
+  /// clearRegisterClasses - remove all register classes
+  void clearRegisterClasses() {
+    for (unsigned i = 0 ; i<array_lengthof(RegClassForVT); i++)
+      RegClassForVT[i] = 0;
+    AvailableRegClasses.clear();
+  }
+
   /// findRepresentativeClass - Return the largest legal super-reg register class
   /// of the register class for the specified type and its associated "cost".
   virtual std::pair<const TargetRegisterClass*, uint8_t>

Modified: llvm/trunk/lib/Target/Mips/Mips16ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Mips/Mips16ISelLowering.cpp?rev=177120&r1=177119&r2=177120&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Mips/Mips16ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/Mips/Mips16ISelLowering.cpp Thu Mar 14 17:02:09 2013
@@ -39,6 +39,14 @@ namespace {
 
 Mips16TargetLowering::Mips16TargetLowering(MipsTargetMachine &TM)
   : MipsTargetLowering(TM) {
+  //
+  // set up as if mips32 and then revert so we can test the mechanism
+  // for switching
+  addRegisterClass(MVT::i32, &Mips::CPURegsRegClass);
+  addRegisterClass(MVT::f32, &Mips::FGR32RegClass);
+  computeRegisterProperties();
+  clearRegisterClasses();
+
   // Set up the register classes
   addRegisterClass(MVT::i32, &Mips::CPU16RegsRegClass);