On Wed, 11 Sep 2013, Jakub Jelinek wrote:
> On Wed, Sep 11, 2013 at 12:00:04PM +0200, Richard Biener wrote:
> > It should make -Og more usable on the branch and as it is quite
> > new I suppose the change qualifies for the branch (I lately
> > moved some passes there for other diagnostic issues).
> >
> > Opinions on generally splitting critical edges before late
> > uninit warnings?
>
> Looks reasonable to me.
Bootstrapped and tested on x86_64-unknonw-linux-gnu and applied.
Richard.
2013-09-11 Richard Biener <rguent...@suse.de>
PR middle-end/58377
* passes.def: Split critical edges before late uninit warning passes.
* tree-cfg.c (pass_split_crit_edges): Implement clone method.
* g++.dg/uninit-pred-4.C: New testcase.
Index: gcc/passes.def
===================================================================
*** gcc/passes.def (revision 202492)
--- gcc/passes.def (working copy)
*************** along with GCC; see the file COPYING3.
*** 249,254 ****
--- 249,257 ----
account for the predicates protecting the set and the use of each
variable. Using a representation like Gated Single Assignment
may help. */
+ /* Split critical edges before late uninit warning to reduce the
+ number of false positives from it. */
+ NEXT_PASS (pass_split_crit_edges);
NEXT_PASS (pass_late_warn_uninitialized);
NEXT_PASS (pass_dse);
NEXT_PASS (pass_forwprop);
*************** along with GCC; see the file COPYING3.
*** 282,287 ****
--- 285,293 ----
/* ??? We do want some kind of loop invariant motion, but we possibly
need to adjust LIM to be more friendly towards preserving accurate
debug information here. */
+ /* Split critical edges before late uninit warning to reduce the
+ number of false positives from it. */
+ NEXT_PASS (pass_split_crit_edges);
NEXT_PASS (pass_late_warn_uninitialized);
NEXT_PASS (pass_uncprop);
NEXT_PASS (pass_local_pure_const);
Index: gcc/tree-cfg.c
===================================================================
*** gcc/tree-cfg.c (revision 202492)
--- gcc/tree-cfg.c (working copy)
*************** public:
*** 7929,7934 ****
--- 7949,7955 ----
/* opt_pass methods: */
unsigned int execute () { return split_critical_edges (); }
+ opt_pass * clone () { return new pass_split_crit_edges (ctxt_); }
}; // class pass_split_crit_edges
} // anon namespace
Index: gcc/testsuite/g++.dg/uninit-pred-4.C
===================================================================
*** gcc/testsuite/g++.dg/uninit-pred-4.C (revision 0)
--- gcc/testsuite/g++.dg/uninit-pred-4.C (working copy)
***************
*** 0 ****
--- 1,16 ----
+ /* { dg-do compile } */
+ /* { dg-options "-Wuninitialized -Og" } */
+
+ int pop ();
+ int pop_first_bucket;
+
+ int my_pop ()
+ {
+ int out; // { dg-bogus "uninitialized" "uninitialized variable warning" }
+
+ while (pop_first_bucket)
+ if (pop_first_bucket && (out = pop()))
+ return out;
+
+ return 0;
+ }
