257842 2023-06-07 18:44:19 -0700 B3 Select instruction truncates vector operands 2023-06-08 15:32:25 -0700 1 1 1 Unclassified WebKit WebAssembly WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED InRadar P2 Normal --- 1 d_degazio d_degazio webkit-bug-importer oldest_to_newest 1960479 0 d_degazio 2023-06-07 18:44:19 -0700 rdar://108643371 B3 Select lowers to Air using one of several conditional moves, like MoveConditionally64 or MoveDoubleConditionallyFloat. These in turn generate native conditional move instructions, such as fcsel to select between floating-point registers on ARM. However, we don't implement conditional moves for vectors, so when we compile a WASM select instruction with vector operands, B3 ends up treating them like doubles, which ends up zeroing the upper half of the vector register. 1960575 1 d_degazio 2023-06-08 10:51:20 -0700 Pull request: https://github.com/WebKit/WebKit/pull/14778 1960633 2 ews-feeder 2023-06-08 15:32:21 -0700 Committed 264996@main (c4e675b3afdd): <https://commits.webkit.org/264996@main> Reviewed commits have been landed. Closing PR #14778 and removing active labels.