Subzero: Make the register allocator more robust with -reg-use and -reg-exclude.

src/IceClFlags.cpp

 //===- subzero/src/IceClFlags.cpp - Command line flags and parsing --------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 167 matching lines @@
 cl::opt<bool> ShouldDoNopInsertion("nop-insertion",
                                    cl::desc("Randomly insert NOPs"),
                                    cl::init(false));
 
 /// Randomize register allocation.
 cl::opt<bool>
     RandomizeRegisterAllocation("randomize-regalloc",
                                 cl::desc("Randomize register allocation"),
                                 cl::init(false));
 
+/// Allow failsafe access to registers that were restricted via -reg-use or
+/// -reg-exclude.
+cl::opt<bool>
+    RegAllocReserve("reg-reserve",
+                    cl::desc("Let register allocation use reserve registers"),
+                    cl::init(false));
+
 /// Repeat register allocation until convergence.
 cl::opt<bool>
     RepeatRegAlloc("regalloc-repeat",
                    cl::desc("Repeat register allocation until convergence"),
                    cl::init(true));
 
 /// Skip through unimplemented lowering code instead of aborting.
 cl::opt<bool> SkipUnimplemented(
     "skip-unimplemented",
     cl::desc("Skip through unimplemented lowering code instead of aborting."),
@@ skipping 340 matching lines @@
   OutFlags.setPhiEdgeSplit(::EnablePhiEdgeSplit);
   OutFlags.setRandomSeed(::RandomSeed);
   OutFlags.setRandomizeAndPoolImmediatesOption(
       ::RandomizeAndPoolImmediatesOption);
   OutFlags.setRandomizeAndPoolImmediatesThreshold(
       ::RandomizeAndPoolImmediatesThreshold);
   OutFlags.setReorderFunctionsWindowSize(::ReorderFunctionsWindowSize);
   OutFlags.setShouldReorderBasicBlocks(::ReorderBasicBlocks);
   OutFlags.setShouldDoNopInsertion(::ShouldDoNopInsertion);
   OutFlags.setShouldRandomizeRegAlloc(::RandomizeRegisterAllocation);
+  OutFlags.setRegAllocReserve(::RegAllocReserve);
   OutFlags.setShouldRepeatRegAlloc(::RepeatRegAlloc);
   OutFlags.setShouldReorderFunctions(::ReorderFunctions);
   OutFlags.setShouldReorderGlobalVariables(::ReorderGlobalVariables);
   OutFlags.setShouldReorderPooledConstants(::ReorderPooledConstants);
   OutFlags.setSkipUnimplemented(::SkipUnimplemented);
   OutFlags.setSubzeroTimingEnabled(::SubzeroTimingEnabled);
   OutFlags.setTargetArch(::TargetArch);
   OutFlags.setTargetInstructionSet(::TargetInstructionSet);
   OutFlags.setTestPrefix(::TestPrefix);
   OutFlags.setTestStackExtra(::TestStackExtra);
@@ skipping 17 matching lines @@
   OutFlagsExtra.setGenerateBuildAtts(GenerateBuildAtts);
   OutFlagsExtra.setLLVMVerboseErrors(LLVMVerboseErrors);
   OutFlagsExtra.setAppName(AppName);
   OutFlagsExtra.setInputFileFormat(InputFileFormat);
   OutFlagsExtra.setIRFilename(IRFilename);
   OutFlagsExtra.setLogFilename(LogFilename);
   OutFlagsExtra.setOutputFilename(OutputFilename);
 }
 
 } // end of namespace Ice