Turn on FastDSE by default.

Note: FastDSE now equals or exceeds the results of old DSE on all of SPEC2000 and SPEC2006. Unless major problems
show up in the testers, it will likely completely replace old DSE in the near future.

llvm-svn: 39986

llvm/tools/llvm-ld/Optimize.cpp

@@ -168,7 +168,7 @@ void Optimize(Module* M) {
     addPass(Passes, createLICMPass());               // Hoist loop invariants
     addPass(Passes, createLoadValueNumberingPass()); // GVN for load instrs
     addPass(Passes, createGCSEPass());               // Remove common subexprs
-    addPass(Passes, createDeadStoreEliminationPass()); // Nuke dead stores
+    addPass(Passes, createFastDeadStoreEliminationPass()); // Nuke dead stores
 
     // Cleanup and simplify the code after the scalar optimizations.
     addPass(Passes, createInstructionCombiningPass());

llvm/tools/opt/opt.cpp

@@ -291,7 +291,7 @@ void AddStandardCompilePasses(PassManager &PM) {
   addPass(PM, createInstructionCombiningPass());
   addPass(PM, createCondPropagationPass());      // Propagate conditionals
 
-  addPass(PM, createDeadStoreEliminationPass()); // Delete dead stores
+  addPass(PM, createFastDeadStoreEliminationPass()); // Delete dead stores
   addPass(PM, createAggressiveDCEPass());        // SSA based 'Aggressive DCE'
   addPass(PM, createCFGSimplificationPass());    // Merge & remove BBs
   addPass(PM, createSimplifyLibCallsPass());     // Library Call Optimizations