Index: lib/Transforms/Vectorize/SLPVectorizer.cpp
===================================================================
--- lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -3939,6 +3939,36 @@
   return V->getType() < V2->getType();
 }
 
+static Value *getReductionValue(PHINode *P, BasicBlock *ParentBB,
+                                LoopInfo *LI) {
+  Value *Rdx = nullptr;
+
+  if (P->getIncomingBlock(0) == ParentBB) {
+    Rdx = P->getIncomingValue(0);
+  } else if (P->getIncomingBlock(1) == ParentBB) {
+    Rdx = P->getIncomingValue(1);
+  }
+
+  if (Rdx)
+    return Rdx;
+
+  // Otherwise, check whether we have a loop latch to look at.
+  Loop *BBL = LI->getLoopFor(ParentBB);
+  if (!BBL)
+    return Rdx;
+  BasicBlock *BBLatch = BBL->getLoopLatch();
+  if (!BBLatch)
+    return Rdx;
+
+  if (P->getIncomingBlock(0) == BBLatch) {
+    Rdx = P->getIncomingValue(0);
+  } else if (P->getIncomingBlock(1) == BBLatch) {
+    Rdx = P->getIncomingValue(1);
+  }
+
+  return Rdx;
+}
+
 bool SLPVectorizer::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
   bool Changed = false;
   SmallVector<Value *, 4> Incoming;
@@ -4006,11 +4036,9 @@
       // Check that the PHI is a reduction PHI.
       if (P->getNumIncomingValues() != 2)
         return Changed;
-      Value *Rdx =
-          (P->getIncomingBlock(0) == BB
-               ? (P->getIncomingValue(0))
-               : (P->getIncomingBlock(1) == BB ? P->getIncomingValue(1)
-                                               : nullptr));
+
+      Value *Rdx = getReductionValue(P, BB, LI);
+
       // Check if this is a Binary Operator.
       BinaryOperator *BI = dyn_cast_or_null<BinaryOperator>(Rdx);
       if (!BI)
Index: test/Transforms/SLPVectorizer/AArch64/horizontal.ll
===================================================================
--- test/Transforms/SLPVectorizer/AArch64/horizontal.ll
+++ test/Transforms/SLPVectorizer/AArch64/horizontal.ll
@@ -71,3 +71,73 @@
   %s.0.lcssa = phi i32 [ 0, %entry ], [ %add27, %for.end.loopexit ]
   ret i32 %s.0.lcssa
 }
+
+; CHECK-LABEL: select_with_br
+; CHECK: load <4 x i32>
+; CHECK: load <4 x i32>
+; CHECK: select <4 x i1>
+define i32 @select_with_br(i32* noalias nocapture readonly %blk1, i32* noalias nocapture readonly %blk2, i32 %lx, i32 %h, i32 %lim) #0 {
+entry:
+  %cmp.23 = icmp sgt i32 %h, 0
+  br i1 %cmp.23, label %for.body.lr.ph, label %for.end
+
+for.body.lr.ph:                                   ; preds = %entry
+  %idx.ext = sext i32 %lx to i64
+  br label %for.body
+
+for.body:                                         ; preds = %for.body.lr.ph, %if.end.30
+  %s.027 = phi i32 [ 0, %for.body.lr.ph ], [ %add27, %if.end.30 ]
+  %j.026 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %if.end.30 ]
+  %p2.025 = phi i32* [ %blk2, %for.body.lr.ph ], [ %add.ptr32, %if.end.30 ]
+  %p1.024 = phi i32* [ %blk1, %for.body.lr.ph ], [ %add.ptr, %if.end.30 ]
+  %0 = load i32, i32* %p1.024, align 4
+  %1 = load i32, i32* %p2.025, align 4
+  %sub = sub nsw i32 %0, %1
+  %cmp2 = icmp slt i32 %sub, 0
+  %sub3 = sub nsw i32 0, %sub
+  %sub3.sub = select i1 %cmp2, i32 %sub3, i32 %sub
+  %add = add nsw i32 %sub3.sub, %s.027
+  %arrayidx4 = getelementptr inbounds i32, i32* %p1.024, i64 1
+  %2 = load i32, i32* %arrayidx4, align 4
+  %arrayidx5 = getelementptr inbounds i32, i32* %p2.025, i64 1
+  %3 = load i32, i32* %arrayidx5, align 4
+  %sub6 = sub nsw i32 %2, %3
+  %cmp7 = icmp slt i32 %sub6, 0
+  %sub9 = sub nsw i32 0, %sub6
+  %v.1 = select i1 %cmp7, i32 %sub9, i32 %sub6
+  %add11 = add nsw i32 %add, %v.1
+  %arrayidx12 = getelementptr inbounds i32, i32* %p1.024, i64 2
+  %4 = load i32, i32* %arrayidx12, align 4
+  %arrayidx13 = getelementptr inbounds i32, i32* %p2.025, i64 2
+  %5 = load i32, i32* %arrayidx13, align 4
+  %sub14 = sub nsw i32 %4, %5
+  %cmp15 = icmp slt i32 %sub14, 0
+  %sub17 = sub nsw i32 0, %sub14
+  %sub17.sub14 = select i1 %cmp15, i32 %sub17, i32 %sub14
+  %add19 = add nsw i32 %add11, %sub17.sub14
+  %arrayidx20 = getelementptr inbounds i32, i32* %p1.024, i64 3
+  %6 = load i32, i32* %arrayidx20, align 4
+  %arrayidx21 = getelementptr inbounds i32, i32* %p2.025, i64 3
+  %7 = load i32, i32* %arrayidx21, align 4
+  %sub22 = sub nsw i32 %6, %7
+  %cmp23 = icmp slt i32 %sub22, 0
+  %sub25 = sub nsw i32 0, %sub22
+  %v.3 = select i1 %cmp23, i32 %sub25, i32 %sub22
+  %add27 = add nsw i32 %add19, %v.3
+  %cmp28 = icmp slt i32 %add27, %lim
+  br i1 %cmp28, label %if.end.30, label %for.end.loopexit
+
+if.end.30:                                        ; preds = %for.body
+  %add.ptr = getelementptr inbounds i32, i32* %p1.024, i64 %idx.ext
+  %add.ptr32 = getelementptr inbounds i32, i32* %p2.025, i64 %idx.ext
+  %inc = add nuw nsw i32 %j.026, 1
+  %cmp = icmp slt i32 %inc, %h
+  br i1 %cmp, label %for.body, label %for.end.loopexit
+
+for.end.loopexit:                                 ; preds = %for.body, %if.end.30
+  br label %for.end
+
+for.end:                                          ; preds = %for.end.loopexit, %entry
+  %s.1 = phi i32 [ 0, %entry ], [ %add27, %for.end.loopexit ]
+  ret i32 %s.1
+}