swift234

[SIL] Store the BitWidth in the SwitchInstInst instead of computing it

getBitWidthForCase() is called from the destructor of the object and it
used to rely on Operand being around. However, dropAllReferences(), which
is run before instruction destruction makes the operand invalid at the
time of instruction death. (This results in a crash if we were to delete a
SwitchInstInt instruction.)

Swift SVN r8472