[SLPVectorizer] Set flag to previous default.

[asbirlea]

Summary

The refactoring in r360276 moved the RunSLPVectorization flag and added the default explicitly. The default should have been false, as before.

The new pass manager used to have SLPVectorization on by default, now it's off in opt, and needs D61617 checked in to enable it in clang.

[chandlerc]

We should get folks to figure out why this regresses them, but making the two PMs behave the same seems fine for now.

llvm/trunk/lib/Transforms/Vectorize/SLPVectorizer.cpp

 using namespace slpvectorizer;
 
 #define SV_NAME "slp-vectorizer"
 #define DEBUG_TYPE "SLP"
 
 STATISTIC(NumVectorInstructions, "Number of vector instructions generated");
 
 cl::opt<bool>
-    llvm::RunSLPVectorization("vectorize-slp", cl::init(true), cl::Hidden,
+    llvm::RunSLPVectorization("vectorize-slp", cl::init(false), cl::Hidden,
                               cl::desc("Run the SLP vectorization passes"));
 
 static cl::opt<int>
     SLPCostThreshold("slp-threshold", cl::init(0), cl::Hidden,
                      cl::desc("Only vectorize if you gain more than this "
                               "number "));
 
 static cl::opt<bool>

llvm/trunk/test/Other/new-pm-defaults.ll

 ; CHECK-O-NEXT: Running pass: LoopDistributePass
 ; CHECK-O-NEXT: Running pass: LoopVectorizePass
 ; CHECK-O-NEXT: Running analysis: BlockFrequencyAnalysis
 ; CHECK-O-NEXT: Running analysis: BranchProbabilityAnalysis
 ; CHECK-O-NEXT: Running pass: LoopLoadEliminationPass
 ; CHECK-O-NEXT: Running analysis: LoopAccessAnalysis
 ; CHECK-O-NEXT: Running pass: InstCombinePass
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass
-; CHECK-O-NEXT: Running pass: SLPVectorizerPass
 ; CHECK-O-NEXT: Running pass: InstCombinePass
 ; CHECK-O-NEXT: Running pass: LoopUnrollPass
 ; CHECK-O-NEXT: Running pass: WarnMissedTransformationsPass
 ; CHECK-O-NEXT: Running pass: InstCombinePass
 ; CHECK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}OptimizationRemarkEmitterAnalysis
 ; CHECK-O-NEXT: Running pass: FunctionToLoopPassAdaptor<{{.*}}LICMPass
 ; CHECK-O-NEXT: Starting llvm::Function pass manager run.
 ; CHECK-O-NEXT: Running pass: LoopSimplifyPass

llvm/trunk/test/Other/new-pm-thinlto-defaults.ll

 ; CHECK-POSTLINK-O-NEXT: Running pass: LoopDistributePass
 ; CHECK-POSTLINK-O-NEXT: Running pass: LoopVectorizePass
 ; CHECK-POSTLINK-O-NEXT: Running analysis: BlockFrequencyAnalysis
 ; CHECK-POSTLINK-O-NEXT: Running analysis: BranchProbabilityAnalysis
 ; CHECK-POSTLINK-O-NEXT: Running pass: LoopLoadEliminationPass
 ; CHECK-POSTLINK-O-NEXT: Running analysis: LoopAccessAnalysis
 ; CHECK-POSTLINK-O-NEXT: Running pass: InstCombinePass
 ; CHECK-POSTLINK-O-NEXT: Running pass: SimplifyCFGPass
-; CHECK-POSTLINK-O-NEXT: Running pass: SLPVectorizerPass
 ; CHECK-POSTLINK-O-NEXT: Running pass: InstCombinePass
 ; CHECK-POSTLINK-O-NEXT: Running pass: LoopUnrollPass
 ; CHECK-POSTLINK-O-NEXT: Running pass: WarnMissedTransformationsPass
 ; CHECK-POSTLINK-O-NEXT: Running pass: InstCombinePass
 ; CHECK-POSTLINK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}OptimizationRemarkEmitterAnalysis
 ; CHECK-POSTLINK-O-NEXT: Running pass: FunctionToLoopPassAdaptor<{{.*}}LICMPass
 ; CHECK-POSTLINK-O-NEXT: Starting llvm::Function pass manager run
 ; CHECK-POSTLINK-O-NEXT: Running pass: LoopSimplifyPass