On Tue, Mar 21, 2017 at 06:53:34PM +0100, Jakub Jelinek wrote:
> On Tue, Mar 21, 2017 at 08:41:43AM +0100, Jakub Jelinek wrote:
> > On Tue, Mar 21, 2017 at 08:38:20AM +1000, Richard Henderson wrote:
> > > On 03/21/2017 07:15 AM, Jakub Jelinek wrote:
> > > > Not really sure what we should do if both i1 and i2 are frame related,
> > > > shall
> > > > we check for each of the CFA reg notes if they are available and equal?
> > > > Or punt if either of the insns is frame related?
> > >
> > > I would punt if either is frame related.
> >
> > Ok, I'll test then the following patch and gather some statistic on how
> > often we trigger this.
>
> The statistics I've gathered unfortunately shows that at least on
> powerpc64le-linux it is very important to not give up if both i1 and i2
> are frame related and have rtx_equal_p notes.
> I've set on unpatched old_insns_match_p flags when returning non-dir_none
> and checked those flags in the various callers of these when about to
> successfully perform cross-jumping, head-merging etc.
> With /f vs. non-/f, the only 3 hits were on the new pr80102.C testcase
> during powerpc64le-linux bootstrap/regtest, but /f vs. /f there were
> 167601 hits.
Here is updated patch which allows cross-jumping of RTX_FRAME_RELATED_P
insns, as long as they have the same CFA related notes on them (same order
if more than one).
Bootstrapped/regtested on powerpc64le-linux, ok for trunk?
2017-03-21 Jakub Jelinek <ja...@redhat.com>
PR target/80102
* cfgcleanup.c (old_insns_match_p): Don't cross-jump in between /f
and non-/f instructions. If both i1 and i2 are frame related,
verify all CFA notes, their order and content.
* g++.dg/opt/pr80102.C: New test.
--- gcc/cfgcleanup.c.jj 2017-03-21 07:56:55.711233924 +0100
+++ gcc/cfgcleanup.c 2017-03-21 19:20:40.517746664 +0100
@@ -1149,6 +1149,11 @@ old_insns_match_p (int mode ATTRIBUTE_UN
else if (p1 || p2)
return dir_none;
+ /* Do not allow cross-jumping between frame related insns and other
+ insns. */
+ if (RTX_FRAME_RELATED_P (i1) != RTX_FRAME_RELATED_P (i2))
+ return dir_none;
+
p1 = PATTERN (i1);
p2 = PATTERN (i2);
@@ -1207,6 +1212,58 @@ old_insns_match_p (int mode ATTRIBUTE_UN
}
}
+ /* If both i1 and i2 are frame related, verify all the CFA notes
+ in the same order and with the same content. */
+ if (RTX_FRAME_RELATED_P (i1))
+ {
+ static enum reg_note cfa_note_kinds[] = {
+ REG_FRAME_RELATED_EXPR, REG_CFA_DEF_CFA, REG_CFA_ADJUST_CFA,
+ REG_CFA_OFFSET, REG_CFA_REGISTER, REG_CFA_EXPRESSION,
+ REG_CFA_VAL_EXPRESSION, REG_CFA_RESTORE, REG_CFA_SET_VDRAP,
+ REG_CFA_TOGGLE_RA_MANGLE, REG_CFA_WINDOW_SAVE, REG_CFA_FLUSH_QUEUE
+ };
+ rtx n1 = REG_NOTES (i1);
+ rtx n2 = REG_NOTES (i2);
+ unsigned int i;
+ do
+ {
+ /* Skip over reg notes not related to CFI information. */
+ while (n1)
+ {
+ for (i = 0; i < ARRAY_SIZE (cfa_note_kinds); i++)
+ if (REG_NOTE_KIND (n1) == cfa_note_kinds[i])
+ break;
+ if (i != ARRAY_SIZE (cfa_note_kinds))
+ break;
+ n1 = XEXP (n1, 1);
+ }
+ while (n2)
+ {
+ for (i = 0; i < ARRAY_SIZE (cfa_note_kinds); i++)
+ if (REG_NOTE_KIND (n2) == cfa_note_kinds[i])
+ break;
+ if (i != ARRAY_SIZE (cfa_note_kinds))
+ break;
+ n2 = XEXP (n2, 1);
+ }
+ if (n1 == NULL_RTX && n2 == NULL_RTX)
+ break;
+ if (n1 == NULL_RTX || n2 == NULL_RTX)
+ return dir_none;
+ if (XEXP (n1, 0) == XEXP (n2, 0))
+ ;
+ else if (XEXP (n1, 0) == NULL_RTX || XEXP (n2, 0) == NULL_RTX)
+ return dir_none;
+ else if (!(reload_completed
+ ? rtx_renumbered_equal_p (XEXP (n1, 0), XEXP (n2, 0))
+ : rtx_equal_p (XEXP (n1, 0), XEXP (n2, 0))))
+ return dir_none;
+ n1 = XEXP (n1, 1);
+ n2 = XEXP (n2, 1);
+ }
+ while (1);
+ }
+
#ifdef STACK_REGS
/* If cross_jump_death_matters is not 0, the insn's mode
indicates whether or not the insn contains any stack-like
--- gcc/testsuite/g++.dg/opt/pr80102.C.jj 2017-03-21 18:56:30.256698365
+0100
+++ gcc/testsuite/g++.dg/opt/pr80102.C 2017-03-21 18:56:30.256698365 +0100
@@ -0,0 +1,14 @@
+// PR target/80102
+// { dg-do compile }
+// { dg-options "-fnon-call-exceptions -Os" }
+// { dg-additional-options "-mminimal-toc" { target { powerpc*-*-* && lp64 } }
}
+
+struct B { float a; B (float c) { for (int g; g < c;) ++a; } };
+struct D { D (B); };
+
+int
+main ()
+{
+ B (1.0);
+ D e (0.0), f (1.0);
+}
Jakub
