From 4fb3c4bf863f2ab32fee13405f71b6785763e909 Mon Sep 17 00:00:00 2001 From: beetrees Date: Sun, 21 Jul 2024 12:13:58 +0100 Subject: [PATCH] Fix handling of large alignments in `write_cvalue_maybe_transmute` (#1521) --- src/value_and_place.rs | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/src/value_and_place.rs b/src/value_and_place.rs index 1aa28daeafc..8eb2095e523 100644 --- a/src/value_and_place.rs +++ b/src/value_and_place.rs @@ -677,8 +677,10 @@ fn transmute_scalar<'tcx>( let to_addr = to_ptr.get_addr(fx); let src_layout = from.1; let size = dst_layout.size.bytes(); - let src_align = src_layout.align.abi.bytes() as u8; - let dst_align = dst_layout.align.abi.bytes() as u8; + // `emit_small_memory_copy` uses `u8` for alignments, just use the maximum + // alignment that fits in a `u8` if the actual alignment is larger. + let src_align = src_layout.align.abi.bytes().try_into().unwrap_or(128); + let dst_align = dst_layout.align.abi.bytes().try_into().unwrap_or(128); fx.bcx.emit_small_memory_copy( fx.target_config, to_addr,