From d48b249b71628f3a73540734f50c6aae21828566 Mon Sep 17 00:00:00 2001 From: Florian Hahn Date: Sat, 10 Oct 2020 16:39:48 +0100 Subject: [PATCH] [SCEV] Add test cases where the max BTC is imprecise, due to step != 1. Add a test case where we fail to compute a tight max backedge taken count, due to the step being != 1. This is part of the issue with PR40961. --- .../max-backedge-taken-count-guard-info.ll | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info.ll b/llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info.ll index f961c83..489ae76 100644 --- a/llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info.ll +++ b/llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info.ll @@ -135,6 +135,28 @@ exit: ret void } +define void @test_guard_ule_12_step2(i32* nocapture %a, i64 %N) { +; CHECK-LABEL: Determining loop execution counts for: @test_guard_ule_12_step2 +; CHECK-NEXT: Loop %loop: backedge-taken count is (%N /u 2) +; CHECK-NEXT: Loop %loop: max backedge-taken count is 9223372036854775807 +; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is (%N /u 2) +; +entry: + %c.1 = icmp ule i64 %N, 12 + br i1 %c.1, label %loop, label %exit + +loop: + %iv = phi i64 [ %iv.next, %loop ], [ 0, %entry ] + %idx = getelementptr inbounds i32, i32* %a, i64 %iv + store i32 1, i32* %idx, align 4 + %iv.next = add nuw nsw i64 %iv, 2 + %exitcond = icmp eq i64 %iv, %N + br i1 %exitcond, label %exit, label %loop + +exit: + ret void +} + define void @test_multiple_const_guards_order1(i32* nocapture %a, i64 %i) { ; CHECK-LABEL: @test_multiple_const_guards_order1 ; CHECK: Loop %loop: backedge-taken count is %i -- 2.7.4