Strides only in ph

Author: fhahn

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -9190,7 +9190,12 @@ LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(VFRange &Range) {
     auto *CI = Plan->getOrAddLiveIn(
         ConstantInt::get(Stride->getType(), ScevStride->getAPInt()));
     if (VPValue *StrideVPV = Plan->getLiveIn(StrideV))
-      StrideVPV->replaceAllUsesWith(CI);
+      StrideVPV->replaceUsesWithIf(CI, [&Plan](VPUser &U, unsigned) {
+                                      auto *R = dyn_cast<VPRecipeBase>(&U);
+      if (!R)
+        return false;
+      return R->getParent()->getParent() || R->getParent() == Plan->getVectorLoopRegion()->getSinglePredecessor();
+                                      });
 
     // The versioned value may not be used in the loop directly but through a
     // sext/zext. Add new live-ins in those cases.
@@ -9204,7 +9209,12 @@ LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(VFRange &Range) {
       APInt C = isa<SExtInst>(U) ? ScevStride->getAPInt().sext(BW)
                                  : ScevStride->getAPInt().zext(BW);
       VPValue *CI = Plan->getOrAddLiveIn(ConstantInt::get(U->getType(), C));
-      StrideVPV->replaceAllUsesWith(CI);
+      StrideVPV->replaceUsesWithIf(CI, [&Plan](VPUser &U, unsigned) {
+                                      auto *R = dyn_cast<VPRecipeBase>(&U);
+      if (!R)
+        return false;
+      return R->getParent()->getParent() || R->getParent() == Plan->getVectorLoopRegion()->getSinglePredecessor();
+                                      });
     }
   }