http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59919
Jeffrey A. Law <law at redhat dot com> changed:
What |Removed |Added
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Assignee|unassigned at gcc dot gnu.org |law at redhat dot com
--- Comment #5 from Jeffrey A. Law <law at redhat dot com> ---
The problem here is we have a call to a non-returning function. The caller
also calls setjmp.
This ultimately results in something like this prior to vrp:
;; basic block 2, loop depth 0, count 0, freq 10000, maybe hot
;; prev block 0, next block 3, flags: (NEW, REACHABLE)
;; pred: ENTRY [100.0%] (FALLTHRU,EXECUTABLE)
bar (p_3(D));
;; succ: 3 [100.0%] (ABNORMAL,EXECUTABLE)
;; basic block 3, loop depth 0, count 0, freq 10000, maybe hot
;; Invalid sum of incoming frequencies 15000, should be 10000
;; prev block 2, next block 4, flags: (NEW, REACHABLE, IRREDUCIBLE_LOOP)
;; pred: 2 [100.0%] (ABNORMAL,EXECUTABLE)
;; 3 [50.0%] (ABNORMAL,DFS_BACK,IRREDUCIBLE_LOOP,EXECUTABLE)
setjmp (_4(D));
_6 = &p_3(D)->i;
foo (_6);
;; succ: 3 [50.0%] (ABNORMAL,DFS_BACK,IRREDUCIBLE_LOOP,EXECUTABLE)
;; 4 [50.0%] (FALLTHRU,EXECUTABLE)
;; basic block 4, loop depth 0, count 0, freq 5000, maybe hot
;; prev block 3, next block 1, flags: (NEW, REACHABLE)
;; pred: 3 [50.0%] (FALLTHRU,EXECUTABLE)
return;
Note that because "bar" is non-returning there is no normal outgoing edge from
BB2. There is an abnormal edge because our CFG code isn't flow sensitive.
Either way we have a single outgoing edge from BB2 that is abnormal.
We want to insert an assertion because of the non-null attribute. But
process_edge_insertions_for never contemplated this particular situation and we
hit the gcc_unreachable.
Creating an ASSERT_EXPR here is wasteful and preventing that is one potential
solution. Another is to have process_edge_insertions_for not trigger
gcc_unreachable here as it should be safe to just return false for this case.
I'll play a bit with both.
