Switch to llvm::findFirstSet instead of ffs since mingw doesn't have ffs.

src/IceTargetLoweringX8632.cpp

 //===- subzero/src/IceTargetLoweringX8632.cpp - x86-32 lowering -----------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the TargetLoweringX8632 class, which
 // consists almost entirely of the lowering sequence for each
 // high-level instruction.  It also implements
 // TargetX8632Fast::postLower() which does the simplest possible
 // register allocation for the "fast" target.
 //
 //===----------------------------------------------------------------------===//
 
 #include "IceDefs.h"
 #include "IceCfg.h"
 #include "IceCfgNode.h"
 #include "IceClFlags.h"
 #include "IceInstX8632.h"
 #include "IceOperand.h"
 #include "IceTargetLoweringX8632.def"
 #include "IceTargetLoweringX8632.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/Support/MathExtras.h"
 #include "llvm/Support/CommandLine.h"
 
-#include <strings.h>
-
 namespace Ice {
 
 namespace {
 
 // The following table summarizes the logic for lowering the fcmp
 // instruction.  There is one table entry for each of the 16 conditions.
 //
 // The first four columns describe the case when the operands are
 // floating point scalar values.  A comment in lowerFcmp() describes the
 // lowering template.  In the most general case, there is a compare
@@ skipping 509 matching lines @@
   // Sort the variables into buckets according to the log of their width
   // in bytes.
   const SizeT NumBuckets =
       X86_LOG2_OF_MAX_STACK_SLOT_SIZE - X86_LOG2_OF_MIN_STACK_SLOT_SIZE + 1;
   VarList Buckets[NumBuckets];
 
   for (VarList::const_iterator I = Source.begin(), E = Source.end(); I != E;
        ++I) {
     Variable *Var = *I;
     uint32_t NaturalAlignment = typeWidthInBytesOnStack(Var->getType());
-    SizeT LogNaturalAlignment = ffs(NaturalAlignment) - 1;
+    SizeT LogNaturalAlignment = llvm::findFirstSet(NaturalAlignment);
     assert(LogNaturalAlignment >= X86_LOG2_OF_MIN_STACK_SLOT_SIZE);
     assert(LogNaturalAlignment <= X86_LOG2_OF_MAX_STACK_SLOT_SIZE);
     SizeT BucketIndex = LogNaturalAlignment - X86_LOG2_OF_MIN_STACK_SLOT_SIZE;
     Buckets[BucketIndex].push_back(Var);
   }
 
   for (SizeT I = 0, E = NumBuckets; I < E; ++I) {
     VarList &List = Buckets[NumBuckets - I - 1];
     Dest.insert(Dest.end(), List.begin(), List.end());
   }
@@ skipping 3890 matching lines @@
     Str << "\t.align\t" << Align << "\n";
     Str << MangledName << ":\n";
     for (SizeT i = 0; i < Size; ++i) {
       Str << "\t.byte\t" << (((unsigned)Data[i]) & 0xff) << "\n";
     }
     Str << "\t.size\t" << MangledName << ", " << Size << "\n";
   }
 }
 
 } // end of namespace Ice