1; RUN: opt -irce -S < %s | FileCheck %s 2 3define void @decrementing_loop(i32 *%arr, i32 *%a_len_ptr, i32 %n) { 4 entry: 5 %len = load i32, i32* %a_len_ptr, !range !0 6 %first.itr.check = icmp sgt i32 %n, 0 7 %start = sub i32 %n, 1 8 br i1 %first.itr.check, label %loop, label %exit 9 10 loop: 11 %idx = phi i32 [ %start, %entry ] , [ %idx.dec, %in.bounds ] 12 %idx.dec = sub i32 %idx, 1 13 %abc.high = icmp slt i32 %idx, %len 14 %abc.low = icmp sge i32 %idx, 0 15 %abc = and i1 %abc.low, %abc.high 16 br i1 %abc, label %in.bounds, label %out.of.bounds, !prof !1 17 18 in.bounds: 19 %addr = getelementptr i32, i32* %arr, i32 %idx 20 store i32 0, i32* %addr 21 %next = icmp sgt i32 %idx.dec, -1 22 br i1 %next, label %loop, label %exit 23 24 out.of.bounds: 25 ret void 26 27 exit: 28 ret void 29 30; CHECK: loop.preheader: 31; CHECK: [[not_len:[^ ]+]] = sub i32 -1, %len 32; CHECK: [[not_n:[^ ]+]] = sub i32 -1, %n 33; CHECK: [[not_len_hiclamp_cmp:[^ ]+]] = icmp sgt i32 [[not_len]], [[not_n]] 34; CHECK: [[not_len_hiclamp:[^ ]+]] = select i1 [[not_len_hiclamp_cmp]], i32 [[not_len]], i32 [[not_n]] 35; CHECK: [[len_hiclamp:[^ ]+]] = sub i32 -1, [[not_len_hiclamp]] 36; CHECK: [[not_exit_preloop_at_cmp:[^ ]+]] = icmp sgt i32 [[len_hiclamp]], 0 37; CHECK: [[not_exit_preloop_at:[^ ]+]] = select i1 [[not_exit_preloop_at_cmp]], i32 [[len_hiclamp]], i32 0 38; CHECK: %exit.preloop.at = add i32 [[not_exit_preloop_at]], -1 39} 40 41!0 = !{i32 0, i32 2147483647} 42!1 = !{!"branch_weights", i32 64, i32 4} 43