llvm-project/llvm/test/Transforms/IndVarSimplify/tripcount_infinite.ll

; These tests have an infinite trip count.  We obviously shouldn't remove the 
; loops!  :)
;
; RUN: llvm-as < %s | opt -indvars -adce -simplifycfg | llvm-dis | grep icmp | wc -l > %t2
; RUN: llvm-as < %s | llvm-dis | grep icmp | wc -l > %t1
; RUN: diff %t1 %t2

;; test for (i = 1; i != 100; i += 2)
define i32 @infinite_linear() {
entry:
        br label %loop

loop:           ; preds = %loop, %entry
        %i = phi i32 [ 1, %entry ], [ %i.next, %loop ]          ; <i32> [#uses=3]
        %i.next = add i32 %i, 2         ; <i32> [#uses=1]
        %c = icmp ne i32 %i, 100                ; <i1> [#uses=1]
        br i1 %c, label %loop, label %loopexit

loopexit:               ; preds = %loop
        ret i32 %i
}

;; test for (i = 1; i*i != 63; ++i)
define i32 @infinite_quadratic() {
entry:
        br label %loop

loop:           ; preds = %loop, %entry
        %i = phi i32 [ 1, %entry ], [ %i.next, %loop ]          ; <i32> [#uses=4]
        %isquare = mul i32 %i, %i               ; <i32> [#uses=1]
        %i.next = add i32 %i, 1         ; <i32> [#uses=1]
        %c = icmp ne i32 %isquare, 63           ; <i1> [#uses=1]
        br i1 %c, label %loop, label %loopexit

loopexit:               ; preds = %loop
        ret i32 %i
}