On Thu, Jan 09, 2014 at 12:31:47PM +0100, Richard Biener wrote:
> On Thu, 9 Jan 2014, Jakub Jelinek wrote:
>
> > On Thu, Jan 09, 2014 at 12:15:00PM +0100, Richard Biener wrote:
> > > > Well, then the __cxa_pure_virtual testcases ICE again, but the
> > > > pr59622-5.C
> > > > testcase ICEs anyway, so here is a different patch (untested so far
> > > > except
> > > > for the tests). The issue with the calls is that when fold_stmt is done
> > > > during gimplification (or omp lowering), we don't have cfg nor SSA form
> > > > and
> > > > nothing performs fixup_noreturn_calls (that function requires CFG and
> > > > SSA
> > > > form anyway). So, we have to fix that up by hand, but as we aren't in
> > > > SSA
> > > > form yet, dropping lhs is always safe for the noreturn calls.
> > >
> > > Don't we "fix this up" during CFG build?
> >
> > Sure, we do, but we ICE far before we get there.
> > #0 error (gmsgid=0x1613b69 "LHS in noreturn call") at
> > ../../gcc/diagnostic.c:1041
> > #1 0x0000000000d64c7b in verify_gimple_call (stmt=<gimple_call
> > 0x7ffff1a2b000>) at ../../gcc/tree-cfg.c:3149
> > #2 0x0000000000d68e0f in verify_gimple_stmt (stmt=<gimple_call
> > 0x7ffff1a2b000>) at ../../gcc/tree-cfg.c:4323
> > #3 0x0000000000d69430 in verify_gimple_in_seq_2 (stmts=0x7ffff1a232d0) at
> > ../../gcc/tree-cfg.c:4490
> > #4 0x0000000000d69502 in verify_gimple_in_seq (stmts=0x7ffff1a232d0) at
> > ../../gcc/tree-cfg.c:4520
> > #5 0x0000000000af3806 in gimplify_body (fndecl=<function_decl
> > 0x7ffff1a0da00 baz>, do_parms=true) at ../../gcc/gimplify.c:8599
> > #6 0x0000000000af3c40 in gimplify_function_tree (fndecl=<function_decl
> > 0x7ffff1a0da00 baz>) at ../../gcc/gimplify.c:8684
>
> So what fixes it for
>
> int __attribute__((noreturn)) foo () {}
> int main()
> {
> return foo ();
> }
>
> ?
gimplify_modify_expr has:
if (!gimple_call_noreturn_p (assign))
gimple_call_set_lhs (assign, *to_p);
Jakub
