The LIT test cases were migrated with the script provided by
Nikita Popov.
No manual changes were made. Committed without review since
no functional changes, after consultation with uweigand.
The type legalizer has by default no method of doing this bitcast other than
storing and reloading the value from stack.
This patch implements a custom lowering of this operation using extractions
of subregs (z13 and earlier using FP128 register pairs), or of vector
elements (with 'vector enhancements 1' using VR128 FP registers).
Review: Ulrich Weigand
Differential Revision: https://reviews.llvm.org/D110346
