In InnerLoopVectorizer::getOrCreateTripCount, when the backedge taken
count is a SCEV add expression, its type is defined by the type of the
last operand of the add expression.
In the test case from PR45259, this last operand happens to be a
pointer, which (according to llvm::Type) does not have a primitive size
in bits. In this case, LoopVectorize fails to truncate the SCEV and
crashes as a result.
ISTM that the truncation really is needed, and that using
ScalarEvolution::getTypeSizeInBits makes the truncation work as
expected. As I'm not really familiar with this code, I'm not sure
whether this is an appropriate or sufficient fix -- any advice