Imported Upstream version 5.18.0.246

Former-commit-id: 0c7ce5b1a7851e13f22acfd379b7f9fb304e4833

external/llvm/test/Analysis/Lint/tail-call-byval.ll

@@ -0,0 +1,33 @@
+; RUN: opt < %s -lint -disable-output 2>&1 | FileCheck %s
+
+%s = type { i8 }
+
+declare void @f1(%s*)
+
+define void @f2() {
+entry:
+  %c = alloca %s
+  tail call void @f1(%s* %c)
+  ret void
+}
+
+; Lint should complain about the tail call passing the alloca'd value %c to f1.
+; CHECK: Undefined behavior: Call with "tail" keyword references alloca
+; CHECK-NEXT:  tail call void @f1(%s* %c)
+
+declare void @f3(%s* byval)
+
+define void @f4() {
+entry:
+  %c = alloca %s
+  tail call void @f3(%s* byval %c)
+  ret void
+}
+
+; Lint should not complain about passing the alloca'd %c since it's passed
+; byval, effectively copying the data to the stack instead of leaking the
+; pointer itself.
+; CHECK-NOT: Undefined behavior: Call with "tail" keyword references alloca
+; CHECK-NOT:  tail call void @f3(%s* byval %c)
+
+