Index: lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- lib/Transforms/Vectorize/LoopVectorize.cpp
+++ lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -3586,8 +3586,12 @@
       IRBuilder<> B(MiddleBlock->getTerminator());
       Value *CountMinusOne = B.CreateSub(
           CountRoundDown, ConstantInt::get(CountRoundDown->getType(), 1));
-      Value *CMO = B.CreateSExtOrTrunc(CountMinusOne, II.getStep()->getType(),
-                                       "cast.cmo");
+      Value *CMO =
+          !II.getStep()->getType()->isIntegerTy()
+              ? B.CreateCast(Instruction::SIToFP, CountMinusOne,
+                             II.getStep()->getType())
+              : B.CreateSExtOrTrunc(CountMinusOne, II.getStep()->getType());
+      CMO->setName("cast.cmo");
       Value *Escape = II.transform(B, CMO, PSE.getSE(), DL);
       Escape->setName("ind.escape");
       MissingVals[UI] = Escape;
Index: test/Transforms/LoopVectorize/float-induction.ll
===================================================================
--- test/Transforms/LoopVectorize/float-induction.ll
+++ test/Transforms/LoopVectorize/float-induction.ll
@@ -338,3 +338,44 @@
 for.end:
   ret void
 }
+
+; VEC4_INTERL1-LABEL: @external_use(
+; VEC4_INTERL1-NEXT:  entry:
+; VEC4_INTERL1-NEXT:    [[TMP0:%.*]] = icmp sgt i64 %n, 1
+; VEC4_INTERL1-NEXT:    [[SMAX:%.*]] = select i1 [[TMP0]], i64 %n, i64 1
+; VEC4_INTERL1:         br i1 {{.*}}, label %scalar.ph, label %min.iters.checked
+; VEC4_INTERL1:       min.iters.checked:
+; VEC4_INTERL1-NEXT:    [[N_VEC:%.*]] = and i64 [[SMAX]], 9223372036854775804
+; VEC4_INTERL1:         br i1 {{.*}}, label %scalar.ph, label %vector.ph
+; VEC4_INTERL1:       vector.ph:
+; VEC4_INTERL1-NEXT:    br label %vector.body
+; VEC4_INTERL1:       vector.body:
+; VEC4_INTERL1-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %vector.ph ], [ [[INDEX_NEXT:%.*]], %vector.body ]
+; VEC4_INTERL1-NEXT:    [[INDEX_NEXT]] = add i64 [[INDEX]], 4
+; VEC4_INTERL1-NEXT:    [[TMP1:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; VEC4_INTERL1-NEXT:    br i1 [[TMP1]], label %middle.block, label %vector.body
+; VEC4_INTERL1:       middle.block:
+; VEC4_INTERL1:         [[TMP2:%.*]] = add nsw i64 [[N_VEC]], -1
+; VEC4_INTERL1-NEXT:    [[CAST_CMO:%.*]] = sitofp i64 [[TMP2]] to double
+; VEC4_INTERL1-NEXT:    [[IND_ESCAPE:%.*]] = fadd fast double [[CAST_CMO]], %m
+; VEC4_INTERL1-NEXT:    br i1 {{.*}}, label %for.end, label %scalar.ph
+; VEC4_INTERL1:       for.end:
+; VEC4_INTERL1-NEXT:    [[TMP0:%.*]] = phi double [ %j, %for.body ], [ [[IND_ESCAPE]], %middle.block ]
+; VEC4_INTERL1-NEXT:    ret double [[TMP0]]
+
+define double @external_use(double %m, i64 %n) {
+entry:
+  br label %for.body
+
+for.body:
+  %i = phi i64 [ 0, %entry ], [%i.next, %for.body]
+  %j = phi double [ %m, %entry ], [ %j.next, %for.body ]
+  %i.next = add i64 %i, 1
+  %j.next = fadd fast double %j, 1.0
+  %cond = icmp slt i64 %i.next, %n
+  br i1 %cond, label %for.body, label %for.end
+
+for.end:
+  %tmp0 = phi double [ %j, %for.body ]
+  ret double %tmp0
+}