| ; 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 |
| ret i32 37 |
| |
| 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 |
| } |