[InstCombine] Miscompilation when removing freezes

[dtcxzyw]

Reproducer: https://alive2.llvm.org/ce/z/3napog

define i64 @src(i1 %cond) {
  %1 = freeze i64 poison
  %2 = freeze i64 poison
  %ret = select i1 %cond, i64 %1, i64 %2
  ret i64 %ret
}

define i64 @tgt(i1 %cond) {
  ret i64 poison
}

llvm version: 6958633