Index: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -1264,6 +1264,28 @@
       }
     }
 
+    /// Set the operands of this bundle in their original order.
+    void setLoadStoreOperandsInOrder() {
+      assert(Operands.empty() && "Already initialized?");
+      auto *I0 = cast<Instruction>(Scalars[0]);
+      assert((isa<LoadInst>(I0) || isa<StoreInst>(I0)) &&
+             "Expect a load or store instruction");
+      unsigned NumOperands = isa<LoadInst>(I0) ? 1 : 2;
+      Operands.resize(NumOperands);
+      unsigned NumLanes = Scalars.size();
+      for (unsigned OpIdx = 0; OpIdx != NumOperands; ++OpIdx) {
+        Operands[OpIdx].resize(NumLanes);
+        for (unsigned Lane = 0; Lane != NumLanes; ++Lane) {
+          auto *I = cast<Instruction>(Scalars[Lane]);
+          assert(((I->getNumOperands() == NumOperands) ||
+                  (I->getNumOperands() == NumOperands + 1)) &&
+                 "Expected same number of operands (ignoring the "
+                 "noalias_sidechannel");
+          Operands[OpIdx][Lane] = I->getOperand(OpIdx);
+        }
+      }
+    }
+
     /// \returns the \p OpIdx operand of this TreeEntry.
     ValueList &getOperand(unsigned OpIdx) {
       assert(OpIdx < Operands.size() && "Off bounds");
@@ -2445,7 +2467,7 @@
             ++NumOpsWantToKeepOriginalOrder;
             TreeEntry *TE = newTreeEntry(VL, Bundle /*vectorized*/, S,
                                          UserTreeIdx, ReuseShuffleIndicies);
-            TE->setOperandsInOrder();
+            TE->setLoadStoreOperandsInOrder();
             LLVM_DEBUG(dbgs() << "SLP: added a vector of loads.\n");
           } else {
             // Need to reorder.
@@ -2454,7 +2476,7 @@
             TreeEntry *TE =
                 newTreeEntry(VL, Bundle /*vectorized*/, S, UserTreeIdx,
                              ReuseShuffleIndicies, I->getFirst());
-            TE->setOperandsInOrder();
+            TE->setLoadStoreOperandsInOrder();
             LLVM_DEBUG(dbgs() << "SLP: added a vector of jumbled loads.\n");
           }
           return;
@@ -2672,7 +2694,7 @@
       ValueList Operands;
       for (Value *V : VL)
         Operands.push_back(cast<Instruction>(V)->getOperand(0));
-      TE->setOperandsInOrder();
+      TE->setLoadStoreOperandsInOrder();
       buildTree_rec(Operands, Depth + 1, {TE, 0});
       return;
     }
Index: llvm/test/Transforms/SLPVectorizer/noalias.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/SLPVectorizer/noalias.ll
@@ -0,0 +1,55 @@
+; RUN: opt -S < %s -slp-vectorizer -slp-max-reg-size=128 -slp-min-reg-size=128 | FileCheck %s
+
+; SLP vectorization across a @llvm.side.noalias and side channel
+
+; Function Attrs: inaccessiblememonly nounwind willreturn
+declare void @llvm.sideeffect() #0
+
+define void @test(float* %p) {
+; CHECK-LABEL: @test(
+; CHECK-NEXT:    [[P1_DECL:%.*]] = tail call i8* @llvm.noalias.decl.p0i8.p0p0f32.i32(float** null, i32 0, metadata !0)
+; CHECK-NEXT:    [[P0:%.*]] = getelementptr float, float* [[P:%.*]], i64 0
+; CHECK-NEXT:    [[P1:%.*]] = getelementptr float, float* [[P]], i64 1
+; CHECK-NEXT:    [[SIDE_P1:%.*]] = tail call float* @llvm.side.noalias.p0f32.p0i8.p0p0f32.p0p0f32.i32(float* [[P1]], i8* [[P1_DECL]], float** null, float** undef, i32 0, metadata !0), !noalias !0
+; CHECK-NEXT:    [[P2:%.*]] = getelementptr float, float* [[P]], i64 2
+; CHECK-NEXT:    [[P3:%.*]] = getelementptr float, float* [[P]], i64 3
+; CHECK-NEXT:    call void @llvm.sideeffect()
+; CHECK-NEXT:    [[TMP1:%.*]] = bitcast float* [[P0]] to <4 x float>*
+; CHECK-NEXT:    [[TMP2:%.*]] = load <4 x float>, <4 x float>* [[TMP1]], align 4
+; CHECK-NEXT:    call void @llvm.sideeffect()
+; CHECK-NEXT:    [[TMP3:%.*]] = bitcast float* [[P0]] to <4 x float>*
+; CHECK-NEXT:    store <4 x float> [[TMP2]], <4 x float>* [[TMP3]], align 4
+; CHECK-NEXT:    ret void
+;
+  %p1.decl = tail call i8* @llvm.noalias.decl.p0i8.p0p0f32.i32(float** null, i32 0, metadata !0)
+  %p0 = getelementptr float, float* %p, i64 0
+  %p1 = getelementptr float, float* %p, i64 1
+  %side.p1 = tail call float* @llvm.side.noalias.p0f32.p0i8.p0p0f32.p0p0f32.i32(float* %p1, i8* %p1.decl, float** null, float** undef, i32 0, metadata !0), !noalias !0
+  %p2 = getelementptr float, float* %p, i64 2
+  %p3 = getelementptr float, float* %p, i64 3
+  %l0 = load float, float* %p0, !noalias !0
+  %l1 = load float, float* %p1, noalias_sidechannel float* %side.p1, !noalias !0
+  %l2 = load float, float* %p2, !noalias !0
+  call void @llvm.sideeffect()
+  %l3 = load float, float* %p3, !noalias !0
+  store float %l0, float* %p0, !noalias !0
+  call void @llvm.sideeffect()
+  store float %l1, float* %p1, noalias_sidechannel float* %side.p1, !noalias !0
+  store float %l2, float* %p2, !noalias !0
+  store float %l3, float* %p3, !noalias !0
+  ret void
+}
+
+; Function Attrs: argmemonly nounwind
+declare i8* @llvm.noalias.decl.p0i8.p0p0f32.i32(float**, i32, metadata) #1
+
+; Function Attrs: nounwind readnone speculatable
+declare float* @llvm.side.noalias.p0f32.p0i8.p0p0f32.p0p0f32.i32(float*, i8*, float**, float**, i32, metadata) #2
+
+attributes #0 = { inaccessiblememonly nounwind willreturn }
+attributes #1 = { argmemonly nounwind }
+attributes #2 = { nounwind readnone speculatable }
+
+!0 = !{!1}
+!1 = distinct !{!1, !2, !"test_f: p"}
+!2 = distinct !{!2, !"test_f"}