1 files changed, 125 insertions, 0 deletions
diff --git a/llvm/test/Transforms/Inline/cgscc-cycle.ll b/llvm/test/Transforms/Inline/cgscc-cycle.ll
new file mode 100644
index 00000000000..69874c3ef2f
--- /dev/null
+++ b/llvm/test/Transforms/Inline/cgscc-cycle.ll
@@ -0,0 +1,125 @@
+; This test contains extremely tricky call graph structures for the inliner to
+; handle correctly. They form cycles where the inliner introduces code that is
+; immediately or can eventually be transformed back into the original code. And
+; each step changes the call graph and so will trigger iteration. This requires
+; some out-of-band way to prevent infinitely re-inlining and re-transforming the
+; code.
+;
+; RUN: opt < %s -passes='cgscc(inline,function(sroa,instcombine))' -S | FileCheck %s
+
+
+; The `test1_*` collection of functions form a directly cycling pattern.
+
+define void @test1_a(i8** %ptr) {
+; CHECK-LABEL: define void @test1_a(
+entry:
+  call void @test1_b(i8* bitcast (void (i8*, i1, i32)* @test1_b to i8*), i1 false, i32 0)
+; Inlining and simplifying this call will reliably produce the exact same call,
+; over and over again. However, each inlining increments the count, and so we
+; expect this test case to stop after one round of inlining with a final
+; argument of '1'.
+; CHECK-NOT:     call
+; CHECK:         call void @test1_b(i8* bitcast (void (i8*, i1, i32)* @test1_b to i8*), i1 false, i32 1)
+; CHECK-NOT:     call
+
+  ret void
+}
+
+define void @test1_b(i8* %arg, i1 %flag, i32 %inline_count) {
+; CHECK-LABEL: define void @test1_b(
+entry:
+  %a = alloca i8*
+  store i8* %arg, i8** %a
+; This alloca and store should remain through any optimization.
+; CHECK:         %[[A:.*]] = alloca
+; CHECK:         store i8* %arg, i8** %[[A]]
+
+  br i1 %flag, label %bb1, label %bb2
+
+bb1:
+  call void @test1_a(i8** %a) noinline
+  br label %bb2
+
+bb2:
+  %cast = bitcast i8** %a to void (i8*, i1, i32)**
+  %p = load void (i8*, i1, i32)*, void (i8*, i1, i32)** %cast
+  %inline_count_inc = add i32 %inline_count, 1
+  call void %p(i8* %arg, i1 %flag, i32 %inline_count_inc)
+; And we should continue to load and call indirectly through optimization.
+; CHECK:         %[[CAST:.*]] = bitcast i8** %[[A]] to void (i8*, i1, i32)**
+; CHECK:         %[[P:.*]] = load void (i8*, i1, i32)*, void (i8*, i1, i32)** %[[CAST]]
+; CHECK:         call void %[[P]](
+
+  ret void
+}
+
+define void @test2_a(i8** %ptr) {
+; CHECK-LABEL: define void @test2_a(
+entry:
+  call void @test2_b(i8* bitcast (void (i8*, i8*, i1, i32)* @test2_b to i8*), i8* bitcast (void (i8*, i8*, i1, i32)* @test2_c to i8*), i1 false, i32 0)
+; Inlining and simplifying this call will reliably produce the exact same call,
+; but only after doing two rounds if inlining, first from @test2_b then
+; @test2_c. We check the exact number of inlining rounds before we cut off to
+; break the cycle by inspecting the last paramater that gets incremented with
+; each inlined function body.
+; CHECK-NOT:     call
+; CHECK:         call void @test2_b(i8* bitcast (void (i8*, i8*, i1, i32)* @test2_b to i8*), i8* bitcast (void (i8*, i8*, i1, i32)* @test2_c to i8*), i1 false, i32 2)
+; CHECK-NOT:     call
+  ret void
+}
+
+define void @test2_b(i8* %arg1, i8* %arg2, i1 %flag, i32 %inline_count) {
+; CHECK-LABEL: define void @test2_b(
+entry:
+  %a = alloca i8*
+  store i8* %arg2, i8** %a
+; This alloca and store should remain through any optimization.
+; CHECK:         %[[A:.*]] = alloca
+; CHECK:         store i8* %arg2, i8** %[[A]]
+
+  br i1 %flag, label %bb1, label %bb2
+
+bb1:
+  call void @test2_a(i8** %a) noinline
+  br label %bb2
+
+bb2:
+  %p = load i8*, i8** %a
+  %cast = bitcast i8* %p to void (i8*, i8*, i1, i32)*
+  %inline_count_inc = add i32 %inline_count, 1
+  call void %cast(i8* %arg1, i8* %arg2, i1 %flag, i32 %inline_count_inc)
+; And we should continue to load and call indirectly through optimization.
+; CHECK:         %[[CAST:.*]] = bitcast i8** %[[A]] to void (i8*, i8*, i1, i32)**
+; CHECK:         %[[P:.*]] = load void (i8*, i8*, i1, i32)*, void (i8*, i8*, i1, i32)** %[[CAST]]
+; CHECK:         call void %[[P]](
+
+  ret void
+}
+
+define void @test2_c(i8* %arg1, i8* %arg2, i1 %flag, i32 %inline_count) {
+; CHECK-LABEL: define void @test2_c(
+entry:
+  %a = alloca i8*
+  store i8* %arg1, i8** %a
+; This alloca and store should remain through any optimization.
+; CHECK:         %[[A:.*]] = alloca
+; CHECK:         store i8* %arg1, i8** %[[A]]
+
+  br i1 %flag, label %bb1, label %bb2
+
+bb1:
+  call void @test2_a(i8** %a) noinline
+  br label %bb2
+
+bb2:
+  %p = load i8*, i8** %a
+  %cast = bitcast i8* %p to void (i8*, i8*, i1, i32)*
+  %inline_count_inc = add i32 %inline_count, 1
+  call void %cast(i8* %arg1, i8* %arg2, i1 %flag, i32 %inline_count_inc)
+; And we should continue to load and call indirectly through optimization.
+; CHECK:         %[[CAST:.*]] = bitcast i8** %[[A]] to void (i8*, i8*, i1, i32)**
+; CHECK:         %[[P:.*]] = load void (i8*, i8*, i1, i32)*, void (i8*, i8*, i1, i32)** %[[CAST]]
+; CHECK:         call void %[[P]](
+
+  ret void
+}