Subzero: Make liveness validation errors easier to interpret.

src/IceTargetLoweringX86BaseImpl.h

 //===- subzero/src/IceTargetLoweringX86BaseImpl.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 505 matching lines @@
 
   // Register allocation. This requires instruction renumbering and full
   // liveness analysis. Loops must be identified before liveness so variable
   // use weights are correct.
   Func->renumberInstructions();
   if (Func->hasError())
     return;
   Func->liveness(Liveness_Intervals);
   if (Func->hasError())
     return;
+  // 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");
   // Validate the live range computations. The expensive validation call is
   // deliberately only made when assertions are enabled.
   assert(Func->validateLiveness());
-  // 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(VMK_All);
   regAlloc(RAK_Global);
   if (Func->hasError())
     return;
   Func->dump("After linear scan regalloc");
 
   if (getFlags().getEnablePhiEdgeSplit()) {
     Func->advancedPhiLowering();
     Func->dump("After advanced Phi lowering");
   }
@@ skipping 7428 matching lines @@
         emitGlobal(*Var, SectionSuffix);
       }
     }
   } break;
   }
 }
 } // end of namespace X86NAMESPACE
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGX86BASEIMPL_H