swift

fbf4bb73 - [SIMD] Add CustomDebugStringConvertible conformance for SIMD types.

[SIMD] Add CustomDebugStringConvertible conformance for SIMD types. The old SIMD types had a conformance to CustomDebugStringConvertible, but the new ones do not, causing a source compatibility regression. Add back a CustomDebugStringConvertible conformance. Fixes rdar://problem/46746829.