Subzero: Allow builds with assertions disabled.

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
@@ skipping 336 matching lines @@
     return;
 
   // Register allocation.  This requires instruction renumbering and
   // full liveness analysis.
   Func->renumberInstructions();
   if (Func->hasError())
     return;
   Func->liveness(Liveness_Intervals);
   if (Func->hasError())
     return;
-  // Validate the live range computations.  Do it outside the timing
-  // code.  TODO: Put this under a flag.
-  bool ValidLiveness = Func->validateLiveness();
-  assert(ValidLiveness);
-  (void)ValidLiveness; // used only in assert()
+  // Validate the live range computations.  The expensive validation
+  // call is deliberately only made when assertions are enabled.
+  assert(Func->validateLiveness());
   ComputedLiveRanges = true;
   // The post-codegen dump is done here, after liveness analysis and
   // associated cleanup, to make the dump cleaner and more useful.
   Func->dump("After initial x8632 codegen");
   Func->getVMetadata()->init();
   regAlloc();
   if (Func->hasError())
     return;
   Func->dump("After linear scan regalloc");
 
@@ skipping 4154 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