swift234

LoopRotate: canonicalize Struct BB args after UpdateSSA.

Without this, IndvarAnalysis can spuriously fail.

Roughly:
%i0 = integer_literal
%s0 = struct %i0
br (%i0, %s0)

bb(%i1, %s1)

Becomes:
%i0 = integer_literal
br (%i0)

bb(%i1)
%s0 = struct %i1

Swift SVN r23606