Subzero: Improve handling of alloca instructions of constant size.

src/IceTargetLoweringX86Base.h

 //===- subzero/src/IceTargetLoweringX86Base.h - x86 lowering ----*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 110 matching lines @@
   template <typename T = Traits>
   typename std::enable_if<!T::Is64Bit, Operand>::type *
   hiOperand(Operand *Operand);
   template <typename T = Traits>
   typename std::enable_if<T::Is64Bit, Operand>::type *hiOperand(Operand *) {
     llvm::report_fatal_error(
         "Hey, yo! This is x86-64. Watcha doin'? (hiOperand)");
   }
 
   void finishArgumentLowering(Variable *Arg, Variable *FramePtr,
-                              size_t BasicFrameOffset, size_t &InArgsSizeBytes);
+                              size_t BasicFrameOffset, size_t StackAdjBytes,
+                              size_t &InArgsSizeBytes);
   typename Traits::Address stackVarToAsmOperand(const Variable *Var) const;
 
   typename Traits::InstructionSet getInstructionSet() const {
     return InstructionSet;
   }
   Operand *legalizeUndef(Operand *From, int32_t RegNum = Variable::NoRegister);
 
 protected:
   explicit TargetX86Base(Cfg *Func);
 
@@ skipping 526 matching lines @@
   };
 
   bool optimizeScalarMul(Variable *Dest, Operand *Src0, int32_t Src1);
   void findRMW();
 
   typename Traits::InstructionSet InstructionSet =
       Traits::InstructionSet::Begin;
   bool IsEbpBasedFrame = false;
   bool NeedsStackAlignment = false;
   size_t SpillAreaSizeBytes = 0;
+  size_t FixedAllocaSizeBytes = 0;
   std::array<llvm::SmallBitVector, IceType_NUM> TypeToRegisterSet;
   std::array<llvm::SmallBitVector, Traits::RegisterSet::Reg_NUM>
       RegisterAliases;
   llvm::SmallBitVector ScratchRegs;
   llvm::SmallBitVector RegsUsed;
   std::array<VarList, IceType_NUM> PhysicalRegisters;
 
   /// Randomize a given immediate operand
   Operand *randomizeOrPoolImmediate(Constant *Immediate,
                                     int32_t RegNum = Variable::NoRegister);
@@ skipping 26 matching lines @@
   }
 
   BoolFolding FoldingInfo;
 };
 } // end of namespace X86Internal
 } // end of namespace Ice
 
 #include "IceTargetLoweringX86BaseImpl.h"
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGX86BASE_H