From 9281503e8f7573b09e151c0de89dbcb682b288be Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Sat, 2 Jun 2018 01:29:01 +0000
Subject: [PM/LoopUnswitch] Fix how the cloned loops are handled when updating
 analyses.

Summary:
I noticed this issue because we didn't put the primary cloned loop into
the `NonChildClonedLoops` vector and so never iterated on it. Once
I fixed that, it made it clear why I had to do a really complicated and
unnecesasry dance when updating the loops to remain in canonical form --
I was unwittingly working around the fact that the primary cloned loop
wasn't in the expected list of cloned loops. Doh!

Now that we include it in this vector, we don't need to return it and we
can consolidate the update logic as we correctly have a single place
where it can be handled.

I've just added a test for the iteration order aspect as every time
I changed the update logic partially or incorrectly here, an existing
test failed and caught it so that seems well covered (which is also
evidenced by the extensive working around of this missing update).

Reviewers: asbirlea, sanjoy

Subscribers: mcrosier, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D47647

llvm-svn: 333811
---
 .../SimpleLoopUnswitch/nontrivial-unswitch.ll      | 101 +++++++++++++++++++++
 1 file changed, 101 insertions(+)

(limited to 'llvm/test/Transforms')

diff --git a/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch.ll b/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch.ll
index 51afdf386e5..1a14bd209d1 100644
--- a/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch.ll
+++ b/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch.ll
@@ -2562,3 +2562,104 @@ outer.latch:
 exit:
   ret void
 }
+
+; Non-trivial loop unswitching where there are two invariant conditions, but the
+; second one is only in the cloned copy of the loop after unswitching.
+define i32 @test24(i1* %ptr, i1 %cond1, i1 %cond2) {
+; CHECK-LABEL: @test24(
+entry:
+  br label %loop_begin
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br i1 %cond1, label %entry.split.us, label %entry.split
+
+loop_begin:
+  br i1 %cond1, label %loop_a, label %loop_b
+
+loop_a:
+  br i1 %cond2, label %loop_a_a, label %loop_a_c
+; The second unswitched condition.
+;
+; CHECK:       entry.split.us:
+; CHECK-NEXT:    br i1 %cond2, label %entry.split.us.split.us, label %entry.split.us.split
+
+loop_a_a:
+  call void @a()
+  br label %latch
+; The 'loop_a_a' unswitched loop.
+;
+; CHECK:       entry.split.us.split.us:
+; CHECK-NEXT:    br label %loop_begin.us.us
+;
+; CHECK:       loop_begin.us.us:
+; CHECK-NEXT:    br label %loop_a.us.us
+;
+; CHECK:       loop_a.us.us:
+; CHECK-NEXT:    br label %loop_a_a.us.us
+;
+; CHECK:       loop_a_a.us.us:
+; CHECK-NEXT:    call void @a()
+; CHECK-NEXT:    br label %latch.us.us
+;
+; CHECK:       latch.us.us:
+; CHECK-NEXT:    %[[V:.*]] = load i1, i1* %ptr
+; CHECK-NEXT:    br i1 %[[V]], label %loop_begin.us.us, label %loop_exit.split.us.split.us
+;
+; CHECK:       loop_exit.split.us.split.us:
+; CHECK-NEXT:    br label %loop_exit.split
+
+loop_a_c:
+  call void @c()
+  br label %latch
+; The 'loop_a_c' unswitched loop.
+;
+; CHECK:       entry.split.us.split:
+; CHECK-NEXT:    br label %loop_begin.us
+;
+; CHECK:       loop_begin.us:
+; CHECK-NEXT:    br label %loop_a.us
+;
+; CHECK:       loop_a.us:
+; CHECK-NEXT:    br label %loop_a_c.us
+;
+; CHECK:       loop_a_c.us:
+; CHECK-NEXT:    call void @c()
+; CHECK-NEXT:    br label %latch
+;
+; CHECK:       latch.us:
+; CHECK-NEXT:    %[[V:.*]] = load i1, i1* %ptr
+; CHECK-NEXT:    br i1 %[[V]], label %loop_begin.us, label %loop_exit.split.us.split
+;
+; CHECK:       loop_exit.split.us.split:
+; CHECK-NEXT:    br label %loop_exit.split
+
+loop_b:
+  call void @b()
+  br label %latch
+; The 'loop_b' unswitched loop.
+;
+; CHECK:       entry.split:
+; CHECK-NEXT:    br label %loop_begin
+;
+; CHECK:       loop_begin:
+; CHECK-NEXT:    br label %loop_b
+;
+; CHECK:       loop_b:
+; CHECK-NEXT:    call void @b()
+; CHECK-NEXT:    br label %latch
+;
+; CHECK:       latch:
+; CHECK-NEXT:    %[[V:.*]] = load i1, i1* %ptr
+; CHECK-NEXT:    br i1 %[[V]], label %loop_begin, label %loop_exit.split
+;
+; CHECK:       loop_exit.split:
+; CHECK-NEXT:    br label %loop_exit
+
+latch:
+  %v = load i1, i1* %ptr
+  br i1 %v, label %loop_begin, label %loop_exit
+
+loop_exit:
+  ret i32 0
+; CHECK:       loop_exit:
+; CHECK-NEXT:    ret
+}
\ No newline at end of file
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