The constant folding for sdiv and udiv has a big discrepancy between the
comments and the code, which looks like a typo. Currently, we're folding
X / undef pretty inconsistently:
0 / undef -> undef
C / undef -> 0
undef / undef -> 0
Whereas the comments state we do X / undef -> undef. The logic that
returns zero is actually commented as doing undef / X -> 0, despite that
the LHS isn't undef in many of the cases that hit it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261813 91177308-0d34-0410-b5e6-96231b3b80d8