clang-cl -EHa doesn't generate calls to @llvm.seh.try.end

[efriedma-quic]

Consider the following:

int volatile *NullPtr = 0;
void foo(), bar();
void baz() {
  try {
    try {
    } catch(...) {
      foo();
      __builtin_unreachable();
    }
    *NullPtr = 0;
  } catch (...) {
    bar();
  }
}
void baz2() {
  try {
    try {
      *NullPtr = 0;
    } catch(...) {
      foo();
      __builtin_unreachable();
    }
  } catch (...) {
    bar();
  }
}

baz() and baz2() currently lower to exactly the same code; that seems unlikely to be correct.

https://godbolt.org/z/f9odrKGEf

[llvmbot]

@llvm/issue-subscribers-clang-codegen

[phoebewang]

Agreed. This contradicts to the description of the design:
Two intrinsic, seh_try_begin() and seh_try_end(), are added for C-code to mark _try boundary and to prevent from exceptions being moved across _try boundary.
It looks it has been moved before the opt pipeline https://godbolt.org/z/7z1dc555W, so yet another FE problem I think.