Hi,

With Tamar's patch 
(https://gcc.gnu.org/pipermail/gcc-patches/2022-November/604880.html) 
enabling the vectorization of early-breaks, I'd like to allow bitfield 
lowering in such loops, which requires the relaxation of allowing 
multiple exits when doing so.  In order to avoid a similar issue to 
PR107275, I hoisted the code that rejects loops with certain types of 
gimple_stmts from 'if_convertible_loop_p_1' to 
'get_loop_body_in_if_conv_order', to avoid trying to lower bitfields in 
loops we are not going to vectorize anyway.  This also ensures 
'ifcvt_local_dce' doesn't accidentally remove statements it shouldn't as 
it will never come across them.  I made sure to add a comment to make 
clear that there is a direct connection between the two and if we were 
to enable vectorization of any other gimple statement we should make 
sure both handle it.

Bootstrapped and regression tested on aarch64-none-linux-gnu and 
x86_64-pc-linux-gnu

gcc/ChangeLog:

         * tree-if-conv.cc (if_convertible_loop_p_1): Move statement 
check loop from here ...
         (get_loop_body_if_conv_order): ... to here.
         (if_convertible_loop_p): Remove single_exit check.
         (tree_if_conversion): Move single_exit check to if-conversion part.

gcc/testsuite/ChangeLog:

         * gcc.dg/vect/vect-bitfield-read-1-not.c: New test.
         * gcc.dg/vect/vect-bitfield-read-2-not.c: New test.
         * gcc.dg/vect/vect-bitfield-read-8.c: New test.
         * gcc.dg/vect/vect-bitfield-read-9.c: New test.