On Fri, Feb 03, 2012 at 09:17:23AM +0100, Zdenek Dvorak wrote:
> > It seems loop-iv.c happily creates shared RTL in lots of places,
> > loop-unroll.c solves that by unsharing everything it adds, this is
> > an attempt to do the same in unswitching to unshare everything iv_analyze
> > came up with.
> >
> > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> I would suggest to move the unsharing to the point where it is clear that
> the rtl will added, i.e.,
>
> loop-unswitch.c:370
> nloop = unswitch_loop (loop, bbs[i], cond, cinsn);
> ->
> nloop = unswitch_loop (loop, bbs[i], copy_rtx_if_shared (cond), cinsn);
You're right, and that also cures the thing that inner unswitch_single_loop
might use again a condition based on the same rtl (or reverse_condition
thereof). Bootstrapped/regtested again on x86_64-linux and i686-linux,
approved by Richard on IRC, committed to trunk. Thanks.
2012-02-03 Jakub Jelinek <ja...@redhat.com>
Zdenek Dvorak <o...@ucw.cz>
PR rtl-optimization/52092
* loop-unswitch.c (unswitch_single_loop): Call copy_rtx_if_shared
on get_iv_value result.
* gcc.c-torture/compile/pr52092.c: New test.
--- gcc/loop-unswitch.c.jj 2010-06-28 15:36:30.000000000 +0200
+++ gcc/loop-unswitch.c 2012-02-03 09:24:24.385450397 +0100
@@ -367,7 +367,7 @@ unswitch_single_loop (struct loop *loop,
fprintf (dump_file, ";; Unswitching loop\n");
/* Unswitch the loop on this condition. */
- nloop = unswitch_loop (loop, bbs[i], cond, cinsn);
+ nloop = unswitch_loop (loop, bbs[i], copy_rtx_if_shared (cond), cinsn);
gcc_assert (nloop);
/* Invoke itself on modified loops. */
--- gcc/testsuite/gcc.c-torture/compile/pr52092.c.jj 2012-02-02
14:11:37.722031008 +0100
+++ gcc/testsuite/gcc.c-torture/compile/pr52092.c 2012-02-02
14:11:14.000000000 +0100
@@ -0,0 +1,25 @@
+/* PR rtl-optimization/52092 */
+
+int a, b, c, d, e, f, g;
+
+void
+foo (void)
+{
+ for (;;)
+ {
+ int *h = 0;
+ int i = 3;
+ int **j = &h;
+ if (e)
+ {
+ c = d || a;
+ g = c ? a : b;
+ if ((char) (i * g))
+ {
+ h = &f;
+ *h = 0;
+ }
+ **j = 0;
+ }
+ }
+}
Jakub
