[LV] Add exit users for recurrences in test, fix names.

Add users of exit values for recurrences to make sure exit value
generation will be checked in a follow-up change.

Also adjusts/fixes naming in the test.

llvm/test/Transforms/LoopVectorize/first-order-recurrence-chains.ll

@@ -649,27 +649,29 @@ exit:
 
 ; Make sure LLVM doesn't generate wrong data in SinkAfter, and causes crash in
 ; loop vectorizer.
-define void @test_crash(ptr %p) {
+define double @test_crash(ptr %p, ptr noalias %a, ptr noalias %b) {
 ; CHECK-LABEL: @test_crash
 ; CHECK-NOT:   vector.body:
 ; CHECK:       ret
 Entry:
   br label %Loop
 
 Loop:
-  %for.1 = phi double [ %iv1, %Loop ], [ 0.000000e+00, %Entry ]
-  %for.2 = phi double [ %iv2, %Loop ], [ 0.000000e+00, %Entry ]
+  %for.1 = phi double [ %l1, %Loop ], [ 0.000000e+00, %Entry ]
+  %for.2 = phi double [ %l2, %Loop ], [ 0.000000e+00, %Entry ]
   %for.3 = phi double [ %for.2, %Loop ], [ 0.000000e+00, %Entry ]
-  %for.4 = phi i64 [ %count, %Loop ], [ 0, %Entry ]
+  %iv = phi i64 [ %iv.next, %Loop ], [ 0, %Entry ]
   %USE_2_INDVARS = fdiv double %for.3, %for.1
   %div = fdiv double 0.000000e+00, %for.1
-  %iv1 = load double, ptr null, align 8
-  %count = add nuw nsw i64 %for.4, 1
-  %iv2 = load double, ptr null, align 8
+  %l1 = load double, ptr %a, align 8
+  %iv.next= add nuw nsw i64 %iv, 1
+  %l2 = load double, ptr %b, align 8
   store double %div, ptr %p, align 8
-  %cond = icmp eq i64 %count, 0
+  %cond = icmp eq i64 %iv.next, 0
   br i1 %cond, label %End, label %Loop
 
 End:
-  ret void
+  %res.1 = fadd double %for.1, %for.2
+  %res.2 = fadd double %res.1, %for.3
+  ret double %res.2
 }