[InstCombine] Fix visitSwitchInst to use right operand types for sub cstexpr
The visitSwitchInst generates SUB constant expressions to recompute the
switch condition. When truncating the condition to a smaller type, SUB
expressions should use the previous type (before trunc) for both
operands. This fixes an assertion crash.
Differential Revision: http://reviews.llvm.org/D6644
rdar://problem/
19191835
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224574
91177308-0d34-0410-b5e6-
96231b3b80d8