Fix the segfault reported in PR 11990.

The sefault occurs due to an infinite loop when the verifier tries to
determine the size of a type of the form "%rt = type { %rt }" while
checking an alloca of the type.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196626 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 37 insertions, 0 deletions

diff --git a/test/Verifier/recursive-type-1.ll b/test/Verifier/recursive-type-1.ll
new file mode 100644
index 0000000000..4a39957595
--- /dev/null
+++ b/test/Verifier/recursive-type-1.ll
@@ -0,0 +1,12 @@
+; RUN: not llvm-as %s -o /dev/null 2>&1 | FileCheck %s
+
+%rt2 = type { i32, { i8, %rt2, i8 }, i32 }
+
+define i32 @main() nounwind {
+entry:
+  ; Check that recursive types trigger an error instead of segfaulting, when
+  ; the recursion isn't through a pointer to the type.
+  ; CHECK: Cannot allocate unsized type
+  %0 = alloca %rt2
+  ret i32 0
+}
diff --git a/test/Verifier/recursive-type-2.ll b/test/Verifier/recursive-type-2.ll
new file mode 100644
index 0000000000..5f2f66fa1b
--- /dev/null
+++ b/test/Verifier/recursive-type-2.ll
@@ -0,0 +1,14 @@
+; RUN: not llvm-as %s -o /dev/null 2>&1 | FileCheck %s
+
+%rt1 = type { i32, { i8, %rt2, i8 }, i32 }
+%rt2 = type { i64, { i6, %rt3 } }
+%rt3 = type { %rt1 }
+
+define i32 @main() nounwind {
+entry:
+  ; Check that mutually recursive types trigger an error instead of segfaulting,
+  ; when the recursion isn't through a pointer to the type.
+  ; CHECK: Cannot allocate unsized type
+  %0 = alloca %rt2
+  ret i32 0
+}
diff --git a/test/Verifier/recursive-type-3.ll b/test/Verifier/recursive-type-3.ll
new file mode 100644
index 0000000000..8968fb5eb6
--- /dev/null
+++ b/test/Verifier/recursive-type-3.ll
@@ -0,0 +1,11 @@
+; RUN: llvm-as %s -o /dev/null 2>&1
+
+%rt2 = type { i32, { i8, %rt2*, i8 }, i32 }
+
+define i32 @main() nounwind {
+entry:
+  ; Check that linked-list-style recursive types where the recursion is through
+  ; a pointer of the type is valid for an alloca.
+  %0 = alloca %rt2
+  ret i32 0
+}