Merge fixed alloca stack adjustments into the prolog

src/IceInst.cpp

Index: src/IceInst.cpp
diff --git a/src/IceInst.cpp b/src/IceInst.cpp
index 96755eb5b054009c4f48e1d7db9ed9c2553ddfa9..bd68e68e5749bf6ecd6475e17a54ccf65831d69e 100644
--- a/src/IceInst.cpp
+++ b/src/IceInst.cpp
@@ -218,8 +218,8 @@ bool Inst::liveness(InstNumberT InstNumber, LivenessBV &Live,
   return true;
 }
 
-InstAlloca::InstAlloca(Cfg *Func, Operand *ByteCount, uint32_t AlignInBytes,
-                       Variable *Dest)
+InstAlloca::InstAlloca(Cfg *Func, Variable *Dest, Operand *ByteCount,
+                       uint32_t AlignInBytes)
     : InstHighLevel(Func, Inst::Alloca, 1, Dest), AlignInBytes(AlignInBytes) {
   // Verify AlignInBytes is 0 or a power of 2.
   assert(AlignInBytes == 0 || llvm::isPowerOf2_32(AlignInBytes));