[PATCH] D34822: [LVI] Constant-propagate a zero extension of the switch condition value through case edges

[Wei Mi via Phabricator via llvm-commits]

wmi added a comment.

I think we can find many similar problems.

  long g;
  void foo(int b) {
    int a = b;  
    g  = a;
    if (b == 3) {
      // assume we have `a = b` here, current LVI should be able to find out `a` equals to 3.
      __builtin_printf("%lx\n", a);
    }
  } 

Is there a way to make LVI more context sensitive, so that when we try to get value info for `a` and call LazyValueInfoImpl::solveBlockValueCast for `a = b` to find out the value info for `b`, we know the context is in the branch instead of the entry block? I just throw out the question and I don't know it is possible or not.


https://reviews.llvm.org/D34822