+; RUN: opt -functionattrs -S < %s | FileCheck %s
+
+; This checks for an iterator wraparound bug in FunctionAttrs. The previous
+; "incorrect" behavior was inferring readonly for the %x argument in @caller.
+; Inferring readonly for %x *is* actually correct, since @va_func is marked
+; readonly, but FunctionAttrs was inferring readonly for the wrong reasons (and
+; we _need_ the readonly on @va_func to trigger the problematic code path). It
+; is possible that in the future FunctionAttrs becomes smart enough to infer
+; readonly for %x for the right reasons, and at that point this test will have
+; to be marked invalid.
+
+declare void @llvm.va_start(i8*)
+declare void @llvm.va_end(i8*)
+
+define void @va_func(i32* readonly %b, ...) readonly nounwind {
+; CHECK-LABEL: define void @va_func(i32* nocapture readonly %b, ...)
+ entry:
+ %valist = alloca i8
+ call void @llvm.va_start(i8* %valist)
+ call void @llvm.va_end(i8* %valist)
+ %x = call i32 @caller(i32* %b)
+ ret void
+}
+
+define i32 @caller(i32* %x) {
+; CHECK-LABEL: define i32 @caller(i32* nocapture %x)
+ entry:
+ call void(i32*,...) @va_func(i32* null, i32 0, i32 0, i32 0, i32* %x)
+ ret i32 42
+}