Tests - Reduction of the GCC5 bug

1 files changed, 11 insertions, 30 deletions

diff --git a/samples/test/gcc5_codegen_bug.rs b/samples/test/gcc5_codegen_bug.rs
index 9dab5a82..fde709b6 100644
--- a/samples/test/gcc5_codegen_bug.rs
+++ b/samples/test/gcc5_codegen_bug.rs
@@ -1,43 +1,24 @@
 // compile-flags: -O
 
+// A reduction of issue #63, where gcc5 (but not 6) will generate invalid code for the following iterator adapter's
+// `next` function (seen in librustc)
 // ::"core"::iter::Map<::"core"::iter::Chain<::"core"::iter::sources::Once<::"syntax"::ast::NodeId/*S*/,>/*S*/,::"core"::iter::Map<::"core"::slice::Iter<::"syntax"::codemap::Spanned<::"syntax"::ast::PathListItem_/*S*/,>/*S*/,>/*S*/,::"rustc"::closure_I_82<::"rustc"::hir::lowering::LoweringContext/*S*/,>/*S*/,>/*S*/,>/*S*/,::"rustc"::closure_I_83<::"rustc"::hir::lowering::LoweringContext/*S*/,>/*S*/,>
-
-#[derive(Copy,Debug)]
-struct NodeId(u32);
-struct Ident(u32);
-struct PathListItem_
-{
-    i: Ident,
-    i2: Option<Ident>,
-    n: NodeId,
-}
-struct Span(u32, u32, u32);
-struct Spanned<T>
-{
-    v: T,
-    sp: Span,
-}
-#[derive(Copy,Debug)]
-struct ItemId {
-    id: NodeId,
-}
+//
+//
 
 fn main()
 {
-    // return iter::once(i.id).chain(imports.iter().map(|import| import.node.id)).map(|id| hir::ItemId { id: id }).collect();
-    //let list = [ Spanned { v: PathListItem_ { i: Ident(0), i2: None, n: NodeId(0) }, sp: Span(1,1,1) } ];
-    let list: [Spanned<PathListItem_>; 0] = [ ];
-
+    // The function call is kinda needed to trigger the bug
+    // - Probably because of how it sets up `rbx` to be non-zero
     println!("{:?}", foo(0, &[]));
-    println!("{:?}", foo(0, &[ Spanned { v: PathListItem_ { i: Ident(0), i2: None, n: NodeId(0) }, sp: Span(1,1,1) } ]));
-    println!("{:?}", foo(0, &vec![]));
 }
 
-fn foo(n: u32, list: &[Spanned<PathListItem_>]) -> Vec<ItemId> {
+// Has to have the second map - even if it's just identity
+fn foo(n: u32, list: &[u32]) -> Vec<u32> {
     Iterator::chain(
-            ::std::iter::once(NodeId(0)),
-            list.iter().map(|v| v.v.n)
-        ).map(|id| ItemId { id: id })
+            ::std::iter::once(0u32),
+            list.iter().map(|v| *v)
+        ).map(|id| id)
         .collect()
 }