Subzero ARM: lower alloca instruction.

src/IceUtils.h

 //===- subzero/src/IceUtils.h - Utility functions ---------------*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares some utility functions.
@@ skipping 43 matching lines @@
   // Check whether the magnitude of value fits in N bits, i.e., whether an
   // (N+1)-bit sign-magnitude representation can hold value.
   template <typename T> static inline bool IsAbsoluteUint(int N, T Value) {
     assert((0 < N) &&
            (static_cast<unsigned int>(N) < (CHAR_BIT * sizeof(Value))));
     if (Value < 0)
       Value = -Value;
     return IsUint(N, Value);
   }
 
+  // Return true if the addition X + Y will cause integer overflow for
+  // integers of type T.
   template <typename T> static inline bool WouldOverflowAdd(T X, T Y) {
     return ((X > 0 && Y > 0 && (X > std::numeric_limits<T>::max() - Y)) ||
             (X < 0 && Y < 0 && (X < std::numeric_limits<T>::min() - Y)));
   }
 
+  // Return true if X is already aligned by N, where N is a power of 2.
   template <typename T> static inline bool IsAligned(T X, intptr_t N) {
     assert(llvm::isPowerOf2_64(N));
     return (X & (N - 1)) == 0;
   }
 
+  // Return Value adjusted to the next highest multiple of Alignment.
+  static inline uint32_t applyAlignment(uint32_t Value, uint32_t Alignment) {
+    assert(llvm::isPowerOf2_32(Alignment));
+    return (Value + Alignment - 1) & -Alignment;
+  }
+
+  // Return amount which must be added to adjust Pos to the next highest
+  // multiple of Align.
   static inline uint64_t OffsetToAlignment(uint64_t Pos, uint64_t Align) {
     assert(llvm::isPowerOf2_64(Align));
     uint64_t Mod = Pos & (Align - 1);
     if (Mod == 0)
       return 0;
     return Align - Mod;
   }
 
+  // Rotate the value bit pattern to the left by shift bits.
   // Precondition: 0 <= shift < 32
   static inline uint32_t rotateLeft32(uint32_t value, uint32_t shift) {
     if (shift == 0)
       return value;
     return (value << shift) | (value >> (32 - shift));
   }
 
+  // Rotate the value bit pattern to the right by shift bits.
   static inline uint32_t rotateRight32(uint32_t value, uint32_t shift) {
     if (shift == 0)
       return value;
     return (value >> shift) | (value << (32 - shift));
   }
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEUTILS_H