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; RUN: opt < %s -tailcallelim -S | grep call | count 3
; PR4323
; Several cases where tail call elimination should not move the load above the
; call, and thus can't eliminate the tail recursion.
@extern_weak_global = extern_weak global i32 ; <i32*> [#uses=1]
; This load can't be safely moved above the call because the load is from an
; extern_weak global and may trap, but the call may unwind before that happens.
define fastcc i32 @no_tailrecelim_1(i32* %a_arg, i32 %a_len_arg, i32 %start_arg) readonly {
entry:
%tmp2 = icmp sge i32 %start_arg, %a_len_arg ; <i1> [#uses=1]
br i1 %tmp2, label %if, label %else
if: ; preds = %entry
unwind
else: ; preds = %entry
%tmp7 = add i32 %start_arg, 1 ; <i32> [#uses=1]
%tmp8 = call fastcc i32 @no_tailrecelim_1(i32* %a_arg, i32 %a_len_arg, i32 %tmp7) ; <i32> [#uses=1]
%tmp9 = load i32* @extern_weak_global ; <i32> [#uses=1]
%tmp10 = add i32 %tmp9, %tmp8 ; <i32> [#uses=1]
ret i32 %tmp10
}
; This load can't be safely moved above the call because function may write to the pointer.
define fastcc i32 @no_tailrecelim_2(i32* %a_arg, i32 %a_len_arg, i32 %start_arg) nounwind {
entry:
%tmp2 = icmp sge i32 %start_arg, %a_len_arg ; <i1> [#uses=1]
br i1 %tmp2, label %if, label %else
if: ; preds = %entry
store i32 1, i32* %a_arg;
ret i32 0;
else: ; preds = %entry
%tmp7 = add i32 %start_arg, 1 ; <i32> [#uses=1]
%tmp8 = call fastcc i32 @no_tailrecelim_2(i32* %a_arg, i32 %a_len_arg, i32 %tmp7) ; <i32> [#uses=1]
%tmp9 = load i32* %a_arg ; <i32> [#uses=1]
%tmp10 = add i32 %tmp9, %tmp8 ; <i32> [#uses=1]
ret i32 %tmp10
}
; This load can't be safely moved above the call because that would change the
; order in which the volatile loads are performed.
define fastcc i32 @no_tailrecelim_3(i32* %a_arg, i32 %a_len_arg, i32 %start_arg) nounwind {
entry:
%tmp2 = icmp sge i32 %start_arg, %a_len_arg ; <i1> [#uses=1]
br i1 %tmp2, label %if, label %else
if: ; preds = %entry
ret i32 0;
else: ; preds = %entry
%tmp7 = add i32 %start_arg, 1 ; <i32> [#uses=1]
%tmp8 = call fastcc i32 @no_tailrecelim_3(i32* %a_arg, i32 %a_len_arg, i32 %tmp7) ; <i32> [#uses=1]
%tmp9 = volatile load i32* %a_arg ; <i32> [#uses=1]
%tmp10 = add i32 %tmp9, %tmp8 ; <i32> [#uses=1]
ret i32 %tmp10
}
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