backport: re PR c/60101 (Long compile times when mixed complex floating point datatypes are used in lengthy expressions)
Backport from mainline
2014-02-12 Jakub Jelinek <jakub@redhat.com>
PR c/60101
* c-common.c (merge_tlist): If copy is true, call new_tlist,
if false, add ADD itself, rather than vice versa.
(verify_tree): For COND_EXPR, don't call merge_tlist with non-zero
copy. For SAVE_EXPR, only call merge_tlist once.