From f8e3b31858219e84dad358e7b9ee4a96b6ee4b5f Mon Sep 17 00:00:00 2001 From: Ralf Jung Date: Sat, 27 Nov 2021 18:17:09 -0500 Subject: [PATCH] Miri: fix alignment check in array initialization --- compiler/rustc_const_eval/src/interpret/step.rs | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/compiler/rustc_const_eval/src/interpret/step.rs b/compiler/rustc_const_eval/src/interpret/step.rs index e6037d561dedc..9299ae2b2b9f8 100644 --- a/compiler/rustc_const_eval/src/interpret/step.rs +++ b/compiler/rustc_const_eval/src/interpret/step.rs @@ -242,11 +242,15 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { let elem_size = first.layout.size; let first_ptr = first.ptr; let rest_ptr = first_ptr.offset(elem_size, self)?; + // For the alignment of `rest_ptr`, we crucially do *not* use `first.align` as + // that place might be more aligned than its type mandates (a `u8` array could + // be 4-aligned if it sits at the right spot in a struct). Instead we use + // `first.layout.align`, i.e., the alignment given by the type. self.memory.copy_repeatedly( first_ptr, first.align, rest_ptr, - first.align, + first.layout.align.abi, elem_size, length - 1, /*nonoverlapping:*/ true,