[VPlan] Add additional FOR hoisting test.

Additional tests for llvm#108945.

Author: fhahn

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

@@ -152,26 +152,51 @@ exit:
 ; incoming value from the previous iteration (for.x.prev) of te latter FOR (for.y).
 ; That means side-effecting user (store i64 %for.y.i64, ptr %gep) of the latter
 ; FOR (for.y) should be moved which is not currently supported.
-define i32 @test_chained_first_order_recurrences_4(ptr %base) {
+define i32 @test_chained_first_order_recurrences_4(ptr %base, i64 %x) {
 ; CHECK-LABEL: 'test_chained_first_order_recurrences_4'
 ; CHECK: No VPlans built.
-
+;
 entry:
   br label %loop
 
+loop:
+  %iv = phi i64 [ %iv.next, %loop ], [ 0, %entry ]
+  %for.x = phi i64 [ %for.x.next, %loop ], [ 0, %entry ]
+  %for.y = phi i32 [ %for.x.prev, %loop ], [ 0, %entry ]
+  %iv.next = add i64 %iv, 1
+  %gep = getelementptr i64, ptr %base, i64 %iv
+  %for.x.prev = trunc i64 %for.x to i32
+  %for.y.i64 = sext i32 %for.y to i64
+  store i64 %for.y.i64, ptr %gep
+  %for.x.next = mul i64 %x, 2
+  %icmp = icmp ugt i64 %iv, 4096
+  br i1 %icmp, label %ret, label %loop
+
 ret:
   ret i32 0
+}
+
+define i32 @test_chained_first_order_recurrences_5_hoist_to_load(ptr %base) {
+; CHECK-LABEL: 'test_chained_first_order_recurrences_5_hoist_to_load'
+; CHECK: No VPlans built.
+;
+entry:
+  br label %loop
 
 loop:
   %iv = phi i64 [ %iv.next, %loop ], [ 0, %entry ]
   %for.x = phi i64 [ %for.x.next, %loop ], [ 0, %entry ]
   %for.y = phi i32 [ %for.x.prev, %loop ], [ 0, %entry ]
   %iv.next = add i64 %iv, 1
   %gep = getelementptr i64, ptr %base, i64 %iv
+  %l = load i64, ptr %gep
   %for.x.prev = trunc i64 %for.x to i32
   %for.y.i64 = sext i32 %for.y to i64
   store i64 %for.y.i64, ptr %gep
-  %for.x.next = mul i64 0, 0
+  %for.x.next = mul i64 %l, 2
   %icmp = icmp ugt i64 %iv, 4096
   br i1 %icmp, label %ret, label %loop
+
+ret:
+  ret i32 0
 }