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; RUN: opt -verify-loop-info -irce -S < %s | FileCheck %s
define void @decrementing_loop(i32 *%arr, i32 *%a_len_ptr, i32 %n) {
entry:
%len = load i32, i32* %a_len_ptr, !range !0
%first.itr.check = icmp sgt i32 %n, 0
%start = sub i32 %n, 1
br i1 %first.itr.check, label %loop, label %exit
loop:
%idx = phi i32 [ %start, %entry ] , [ %idx.dec, %in.bounds ]
%idx.dec = sub i32 %idx, 1
%abc.high = icmp slt i32 %idx, %len
%abc.low = icmp sge i32 %idx, 0
%abc = and i1 %abc.low, %abc.high
br i1 %abc, label %in.bounds, label %out.of.bounds, !prof !1
in.bounds:
%addr = getelementptr i32, i32* %arr, i32 %idx
store i32 0, i32* %addr
%next = icmp sgt i32 %idx.dec, -1
br i1 %next, label %loop, label %exit
out.of.bounds:
ret void
exit:
ret void
; CHECK: loop.preheader:
; CHECK: [[not_len:[^ ]+]] = sub i32 -1, %len
; CHECK: [[not_n:[^ ]+]] = sub i32 -1, %n
; CHECK: [[not_len_hiclamp_cmp:[^ ]+]] = icmp sgt i32 [[not_len]], [[not_n]]
; CHECK: [[not_len_hiclamp:[^ ]+]] = select i1 [[not_len_hiclamp_cmp]], i32 [[not_len]], i32 [[not_n]]
; CHECK: [[len_hiclamp:[^ ]+]] = sub i32 -1, [[not_len_hiclamp]]
; CHECK: [[not_exit_preloop_at_cmp:[^ ]+]] = icmp sgt i32 [[len_hiclamp]], 0
; CHECK: [[not_exit_preloop_at:[^ ]+]] = select i1 [[not_exit_preloop_at_cmp]], i32 [[len_hiclamp]], i32 0
; CHECK: %exit.preloop.at = add i32 [[not_exit_preloop_at]], -1
}
; Make sure that we can eliminate the range check when the loop looks like:
; for (i = len.a - 1; i >= 0; --i)
; b[i] = a[i];
define void @test_01(i32* %a, i32* %b, i32* %a_len_ptr, i32* %b_len_ptr) {
; CHECK-LABEL: test_01
; CHECK: mainloop:
; CHECK-NEXT: br label %loop
; CHECK: loop:
; CHECK: %rc = and i1 true, true
; CHECK: loop.preloop:
entry:
%len.a = load i32, i32* %a_len_ptr, !range !0
%len.b = load i32, i32* %b_len_ptr, !range !0
%first.itr.check = icmp ne i32 %len.a, 0
br i1 %first.itr.check, label %loop, label %exit
loop:
%idx = phi i32 [ %len.a, %entry ] , [ %idx.next, %in.bounds ]
%idx.next = sub i32 %idx, 1
%rca = icmp ult i32 %idx.next, %len.a
%rcb = icmp ult i32 %idx.next, %len.b
%rc = and i1 %rca, %rcb
br i1 %rc, label %in.bounds, label %out.of.bounds, !prof !1
in.bounds:
%el.a = getelementptr i32, i32* %a, i32 %idx.next
%el.b = getelementptr i32, i32* %b, i32 %idx.next
%v = load i32, i32* %el.a
store i32 %v, i32* %el.b
%loop.cond = icmp slt i32 %idx, 2
br i1 %loop.cond, label %exit, label %loop
out.of.bounds:
ret void
exit:
ret void
}
; Same as test_01, but the latch condition is unsigned
define void @test_02(i32* %a, i32* %b, i32* %a_len_ptr, i32* %b_len_ptr) {
; CHECK-LABEL: test_02
; CHECK: mainloop:
; CHECK-NEXT: br label %loop
; CHECK: loop:
; CHECK: %rc = and i1 true, true
; CHECK: loop.preloop:
entry:
%len.a = load i32, i32* %a_len_ptr, !range !0
%len.b = load i32, i32* %b_len_ptr, !range !0
%first.itr.check = icmp ne i32 %len.a, 0
br i1 %first.itr.check, label %loop, label %exit
loop:
%idx = phi i32 [ %len.a, %entry ] , [ %idx.next, %in.bounds ]
%idx.next = sub i32 %idx, 1
%rca = icmp ult i32 %idx.next, %len.a
%rcb = icmp ult i32 %idx.next, %len.b
%rc = and i1 %rca, %rcb
br i1 %rc, label %in.bounds, label %out.of.bounds, !prof !1
in.bounds:
%el.a = getelementptr i32, i32* %a, i32 %idx.next
%el.b = getelementptr i32, i32* %b, i32 %idx.next
%v = load i32, i32* %el.a
store i32 %v, i32* %el.b
%loop.cond = icmp ult i32 %idx, 2
br i1 %loop.cond, label %exit, label %loop
out.of.bounds:
ret void
exit:
ret void
}
!0 = !{i32 0, i32 2147483647}
!1 = !{!"branch_weights", i32 64, i32 4}
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