From c7e69e46c86c3f3785441de45db4b7bc6d26e321 Mon Sep 17 00:00:00 2001
From: Nikita Popov <nikita.ppv@gmail.com>
Date: Sat, 24 Jul 2021 17:00:16 +0200
Subject: [PATCH] [Tests] Add additional tests for incorrect willreturn
 handling (NFC)

Highlight a few of the places that don't handle non-willreturn
calls correctly right now.
---
 llvm/test/Transforms/LICM/sinking.ll               | 22 +++++++++++++++++++++
 .../LoopDeletion/noop-loops-with-subloops.ll       | 23 ++++++++++++++++++++++
 llvm/test/Transforms/SCCP/calltest.ll              |  9 +++++++++
 3 files changed, 54 insertions(+)

diff --git a/llvm/test/Transforms/LICM/sinking.ll b/llvm/test/Transforms/LICM/sinking.ll
index a9c0f45..ee7f633 100644
--- a/llvm/test/Transforms/LICM/sinking.ll
+++ b/llvm/test/Transforms/LICM/sinking.ll
@@ -979,6 +979,28 @@ try.cont:
   ret void
 }
 
+; TODO: Should not get sunk.
+define i32 @not_willreturn(i8* %p) {
+; CHECK-LABEL: @not_willreturn(
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    store volatile i8 0, i8* [[P:%.*]], align 1
+; CHECK-NEXT:    br i1 true, label [[LOOP]], label [[OUT:%.*]]
+; CHECK:       out:
+; CHECK-NEXT:    [[X_LE:%.*]] = call i32 @getv() #[[ATTR5:[0-9]+]]
+; CHECK-NEXT:    ret i32 [[X_LE]]
+;
+  br label %loop
+
+loop:
+  %x = call i32 @getv() nounwind readnone
+  store volatile i8 0, i8* %p
+  br i1 true, label %loop, label %out
+
+out:
+  ret i32 %x
+}
+
 declare void @may_throw()
 declare void @may_throw2()
 declare i32 @__CxxFrameHandler3(...)
diff --git a/llvm/test/Transforms/LoopDeletion/noop-loops-with-subloops.ll b/llvm/test/Transforms/LoopDeletion/noop-loops-with-subloops.ll
index 715915b..9163c9c 100644
--- a/llvm/test/Transforms/LoopDeletion/noop-loops-with-subloops.ll
+++ b/llvm/test/Transforms/LoopDeletion/noop-loops-with-subloops.ll
@@ -394,6 +394,29 @@ exit:
   ret void
 }
 
+; Inner infinite loop hidden behind a call.
+; TODO: Loop should not get deleted.
+define void @not_willreturn() {
+; CHECK-LABEL: @not_willreturn(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %loop
+
+loop:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ]
+  call void @sideeffect() nounwind readonly
+  %iv.next = add nuw i32 %iv, 1
+  %c = icmp ult i32 %iv, 100
+  br i1 %c, label %loop, label %exit
+
+exit:
+  ret void
+}
+
 !1 = !{!"llvm.loop.mustprogress"}
 !2 = distinct !{!2, !1}
 !3 = distinct !{!3, !1}
diff --git a/llvm/test/Transforms/SCCP/calltest.ll b/llvm/test/Transforms/SCCP/calltest.ll
index cf43ea2..de79363 100644
--- a/llvm/test/Transforms/SCCP/calltest.ll
+++ b/llvm/test/Transforms/SCCP/calltest.ll
@@ -33,3 +33,12 @@ define i32 @test_1() {
   %1 = call %empty @has_side_effects()
   ret i32 0
 }
+
+; TODO: Call should not get dropped.
+define i32 @test_not_willreturn() {
+; CHECK-LABEL: @test_not_willreturn(
+; CHECK-NEXT:    ret i32 0
+;
+  %1 = call %empty @has_side_effects() nounwind readonly
+  ret i32 0
+}
-- 
2.7.4