On Thu, Oct 10, 2019 at 06:12:02PM +0200, Paolo Carlini wrote:
> while working on cp_build_binary_op I noticed that the testsuite wasn't
> exercising the warnings in case RROTATE_EXPR / LROTATE_EXPR, even more the
> code handling those tree codes seemed completely unused. Turned out that the
> C front-end doesn't handle those tree codes at all: I'm coming to the
> conclusion that the C++ front-end bits too are now obsolete and may be
> removed, because only the middle-end generates those codes in order to
> implement optimizations. Anything I'm missing? Any additional testing?
I guess it depends on where.
fold_binary_loc certainly has code to create {L,R}ROTATE_EXPR,
just look at
unsigned foo (unsigned x)
{
return (x << 3) + (x >> (__SIZEOF_INT__ * __CHAR_BIT__ - 3));
}
unsigned bar (unsigned x, unsigned y)
{
return (x << y) | (x >> (__SIZEOF_INT__ * __CHAR_BIT__ - y));
}
and the *.original dump.
The cp_build_binary_op case is unlikely to ever trigger, unless we'd rerun
it on cp_folded trees.
cxx_eval_constant_expression is unlikely, because recently we've switched to
performing constexpr evaluation on pre-cp_folded bodies, not sure if we
never encounter folded trees though.
cp_fold itself depends on whether we ever reprocess the already folded
trees, I'd be afraid we could.
pt.c again unlikely, we should be cp_folding only later on.
Jakub
