On 06/21/2018 11:04 AM, Eric Botcazou wrote: > When code is compiled at -O0, the RTL middle-end makes sure that location > information is preserved as much as possible by generating NOPs with the > location information (goto_locus) present on edges in the CFG, if it thinks > that these edges are the only place where a particular location is mentioned. > > The attached patch prevents this from happening in a couple of cases: > 1. if the function has the DECL_IGNORED_P flag set, > 2. if the NOP is emitted by merge_blocks and the 2nd block is a forwarder > block whose outgoing edge has no location, because in this case the location > of the to-be-elided edge is copied onto the aforementioned outgoing edge. > > Tested (GCC and GDB) on x86-64/Linux, applied on the mainline. > > > 2018-06-21 Eric Botcazou <ebotca...@adacore.com> > > * cfgrtl.c (fixup_reorder_chain): Do not emit NOPs in DECL_IGNORED_P > functions. > (rtl_merge_blocks): Likewise. Do not emit a NOP if the location of the > edge can be forwarded. > (cfg_layout_merge_blocks): Likewise. Funny Alex and I were just talking about the need to stuff away debug info on edges for gimple. Attaching it to gimple nops sounds like a fairly straightforward approach :-)
jeff
