swift234

[sil-simplify-cfg] Fold checked_cast_br if a dynamic type of the operand is statically known from alloc_ref

Transforms :

%1 = alloc_ref $B
checked_cast_br [exact] %1 : $B to $B, bb1, bb2

into

br bb1(%1 : $B)

In case when source and destination types do no match, replace by a branch to the failure bb of the checked_cast_br.

Swift SVN r26275