diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
--- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -1523,11 +1523,11 @@
   Type *BTy = BPtr->getType()->getPointerElementType();
   auto &DL = InnermostLoop->getHeader()->getModule()->getDataLayout();
   uint64_t TypeByteSize = DL.getTypeAllocSize(ATy);
+  bool SizesAreSame = TypeByteSize == DL.getTypeAllocSize(BTy);
   uint64_t Stride = std::abs(StrideAPtr);
   const SCEVConstant *C = dyn_cast<SCEVConstant>(Dist);
   if (!C) {
-    if (!isa<SCEVCouldNotCompute>(Dist) &&
-        TypeByteSize == DL.getTypeAllocSize(BTy) &&
+    if (!isa<SCEVCouldNotCompute>(Dist) && SizesAreSame &&
         isSafeDependenceDistance(DL, *(PSE.getSE()),
                                  *(PSE.getBackedgeTakenCount()), *Dist, Stride,
                                  TypeByteSize))
@@ -1542,7 +1542,7 @@
   int64_t Distance = Val.getSExtValue();
 
   // Attempt to prove strided accesses independent.
-  if (std::abs(Distance) > 0 && Stride > 1 && ATy == BTy &&
+  if (std::abs(Distance) > 0 && Stride > 1 && SizesAreSame &&
       areStridedAccessesIndependent(std::abs(Distance), Stride, TypeByteSize)) {
     LLVM_DEBUG(dbgs() << "LAA: Strided accesses are independent\n");
     return Dependence::NoDep;
@@ -1563,21 +1563,19 @@
   }
 
   // Write to the same location with the same size.
-  // Could be improved to assert type sizes are the same (i32 == float, etc).
   if (Val == 0) {
-    if (ATy == BTy)
+    if (SizesAreSame)
       return Dependence::Forward;
     LLVM_DEBUG(
-        dbgs() << "LAA: Zero dependence difference but different types\n");
+        dbgs() << "LAA: Zero dependence difference but different type sizes\n");
     return Dependence::Unknown;
   }
 
   assert(Val.isStrictlyPositive() && "Expect a positive value");
 
-  if (ATy != BTy) {
-    LLVM_DEBUG(
-        dbgs()
-        << "LAA: ReadWrite-Write positive dependency with different types\n");
+  if (!SizesAreSame) {
+    LLVM_DEBUG(dbgs() << "LAA: ReadWrite-Write positive dependency with "
+                         "different type sizes\n");
     return Dependence::Unknown;
   }
 
diff --git a/llvm/test/Analysis/LoopAccessAnalysis/depend_diff_types.ll b/llvm/test/Analysis/LoopAccessAnalysis/depend_diff_types.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Analysis/LoopAccessAnalysis/depend_diff_types.ll
@@ -0,0 +1,54 @@
+; RUN: opt -S -tbaa -loop-accesses -analyze -enable-new-pm=0 < %s | FileCheck %s
+; RUN: opt -S -disable-output -passes='require<scalar-evolution>,require<tbaa>,require<aa>,loop(print-access-info)' < %s 2>&1 | FileCheck %s
+
+; In the function below some of the accesses are done as double types and some
+; are done as i64 types. When doing dependence analysis the type should not
+; matter if it can be determined that they are the same size.
+
+; CHECK-LABEL: function 'backdep_type_size_equivalence':
+; CHECK:   loop:
+; CHECK:     Memory dependences are safe with a maximum dependence distance of 800 bytes
+; CHECK:     Dependences:
+; CHECK:       Forward:
+; CHECK:           %2 = load double, double* %1, align 8 ->
+; CHECK:           store i64 %indvars.iv, i64* %0, align 8
+
+; CHECK:       Forward:
+; CHECK:           %2 = load double, double* %1, align 8 ->
+; CHECK:           store double %3, double* %6, align 8
+
+; CHECK:       BackwardVectorizable:
+; CHECK:           store double %3, double* %6, align 8 ->
+; CHECK:           store i64 %indvars.iv, i64* %0, align 8
+
+define void @backdep_type_size_equivalence(i64* nocapture %vec, i64 %n) {
+entry:
+  br label %loop
+
+  loop:
+    %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %loop ]
+
+    ;; Load from vec[indvars.iv] as double
+    %0 = getelementptr i64, i64* %vec, i64 %indvars.iv
+    %1 = bitcast i64* %0 to double*
+    %2 = load double, double* %1, align 8
+    %3 = fmul fast double %2, 5.0
+
+    ;; Store to vec[indvars.iv - 100] as double
+    %4 = add nsw i64 %indvars.iv, -100
+    %5 = getelementptr i64, i64* %vec, i64 %4
+    %6 = bitcast i64* %5 to double*
+    store double %3, double* %6, align 8
+
+    ;; Store to vec[indvars.iv] as i64, creating a backwards dependency between
+    ;; the two stores with different element types but the same element size.
+    store i64 %indvars.iv, i64* %0, align 8
+
+    ;; Loop condition.
+    %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+    %cond = icmp eq i64 %indvars.iv.next, %n
+    br i1 %cond, label %exit, label %loop
+
+  exit:
+    ret void
+}