1 files changed, 11 insertions, 3 deletions
diff --git a/llvm/lib/Passes/PassBuilderPipelines.cpp b/llvm/lib/Passes/PassBuilderPipelines.cpp
index 3f41618..2fe963b 100644
--- a/llvm/lib/Passes/PassBuilderPipelines.cpp
+++ b/llvm/lib/Passes/PassBuilderPipelines.cpp
@@ -1298,10 +1298,18 @@ PassBuilder::buildModuleSimplificationPipeline(OptimizationLevel Level,
 
 /// TODO: Should LTO cause any differences to this set of passes?
 void PassBuilder::addVectorPasses(OptimizationLevel Level,
-                                  FunctionPassManager &FPM, bool IsFullLTO) {
+                                  FunctionPassManager &FPM,
+                                  ThinOrFullLTOPhase LTOPhase) {
+  const bool IsFullLTO = LTOPhase == ThinOrFullLTOPhase::FullLTOPostLink;
+
   FPM.addPass(LoopVectorizePass(
       LoopVectorizeOptions(!PTO.LoopInterleaving, !PTO.LoopVectorization)));
 
+  // Drop dereferenceable assumes after vectorization, as they are no longer
+  // needed and can inhibit further optimization.
+  if (!isLTOPreLink(LTOPhase))
+    FPM.addPass(DropUnnecessaryAssumesPass(/*DropDereferenceable=*/true));
+
   FPM.addPass(InferAlignmentPass());
   if (IsFullLTO) {
     // The vectorizer may have significantly shortened a loop body; unroll
@@ -1572,7 +1580,7 @@ PassBuilder::buildModuleOptimizationPipeline(OptimizationLevel Level,
   // from the TargetLibraryInfo.
   OptimizePM.addPass(InjectTLIMappings());
 
-  addVectorPasses(Level, OptimizePM, /* IsFullLTO */ false);
+  addVectorPasses(Level, OptimizePM, LTOPhase);
 
   invokeVectorizerEndEPCallbacks(OptimizePM, Level);
 
@@ -2162,7 +2170,7 @@ PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level,
 
   MainFPM.addPass(LoopDistributePass());
 
-  addVectorPasses(Level, MainFPM, /* IsFullLTO */ true);
+  addVectorPasses(Level, MainFPM, ThinOrFullLTOPhase::FullLTOPostLink);
 
   invokeVectorizerEndEPCallbacks(MainFPM, Level);