> -----Original Message-----
> From: Richard Henderson [mailto:r...@redhat.com]
> Sent: Thursday, November 06, 2014 4:23 PM
> To: Zhenqiang Chen; 'Jan-Benedict Glaw'; Hartmut Penner; Ulrich Weigand;
> Andreas Krebbel
> Cc: gcc-patches@gcc.gnu.org
> Subject: Re: [PATCH, ifcvt] Allow CC mode if HAVE_cbranchcc4 (fix s390
build)
>
> On 11/06/2014 08:44 AM, Zhenqiang Chen wrote:
> > Hi,
> >
> > The patch add runtime check to fix s390 build fail
> > (https://gcc.gnu.org/ml/gcc-patches/2014-11/msg00050.html).
> >
> > And there is additional code to workaround s390 cstorecc4 issue.
> >
> > Bootstrap and no make check regression on X86-64.
> > Build s390-linux-gnu and s390x-linux-gnu.
> >
> > I do not have env to run full s390 tests. Would anyone in the TO list
> > help to run the s390 tests?
> >
> > Thanks!
> > -Zhenqiang
> >
> > ChangeLog:
> > 2014-11-06 Zhenqiang Chen <zhenqiang.c...@arm.com>
> >
> > * ifcvt.c (noce_emit_cmove, noce_get_alt_condition,
> > noce_get_condition):
> > Allow CC mode if HAVE_cbranchcc4.
> > (noce_emit_store_flag): Change CC REG as cond_complex.
> >
> > diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c index f4002f9..7f7b7c1 100644
> > --- a/gcc/ifcvt.c
> > +++ b/gcc/ifcvt.c
> > @@ -849,7 +849,10 @@ noce_emit_store_flag (struct noce_if_info
> > *if_info, rtx x, int reversep,
> > enum rtx_code code;
> >
> > cond_complex = (! general_operand (XEXP (cond, 0), VOIDmode)
> > - || ! general_operand (XEXP (cond, 1), VOIDmode));
> > + || ! general_operand (XEXP (cond, 1), VOIDmode)
> > + /* For s390, CC REG is general_operand. But cstorecc4
> > only
> > + handles CCZ1, which can not handle others like CCU.
> > */
> > + || GET_MODE_CLASS (GET_MODE (XEXP (cond, 0))) ==
> MODE_CC);
> >
>
> I'd like to know more about this. This seems like a mistake in the
backend.
>
> > +#ifdef HAVE_cbranchcc4
> > + if (GET_MODE_CLASS (GET_MODE (cmp_a)) != MODE_CC
> > + || cmp_b != const0_rtx
> > + || !(HAVE_cbranchcc4))
> > +#endif
>
> Please add
>
> #ifndef HAVE_cbranchcc4
> # define HAVE_cbranchcc4
> #endif
>
> at the top of ifcvt.c along with all of the others. Then use normal C
tests
> instead of preprocessor tests.
Thanks for the comment.
> > + int allow_cc_mode = false;
> > +#ifdef HAVE_cbranchcc4
> > + allow_cc_mode = HAVE_cbranchcc4;
> > +#endif
>
> E.g. this becomes
>
> bool allow_cc_mode = HAVE_cbranchcc4;
After adding HAVE_cbranchcc4, we can just use HAVE_cbranchcc4. No need to
add a local variable allow_cc_mode.
Here is the updated patch.
diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c
index f4002f9..21f08c2 100644
--- a/gcc/ifcvt.c
+++ b/gcc/ifcvt.c
@@ -75,6 +75,10 @@
+ 1)
#endif
+#ifndef HAVE_cbranchcc4
+#define HAVE_cbranchcc4 0
+#endif
+
#define IFCVT_MULTIPLE_DUMPS 1
#define NULL_BLOCK ((basic_block) NULL)
@@ -1459,10 +1463,16 @@ noce_emit_cmove (struct noce_if_info *if_info, rtx
x, enum rtx_code code,
end_sequence ();
}
- /* Don't even try if the comparison operands are weird. */
+ /* Don't even try if the comparison operands are weird
+ except that the target supports cbranchcc4. */
if (! general_operand (cmp_a, GET_MODE (cmp_a))
|| ! general_operand (cmp_b, GET_MODE (cmp_b)))
- return NULL_RTX;
+ {
+ if (!(HAVE_cbranchcc4)
+ || GET_MODE_CLASS (GET_MODE (cmp_a)) != MODE_CC
+ || cmp_b != const0_rtx)
+ return NULL_RTX;
+ }
#if HAVE_conditional_move
unsignedp = (code == LTU || code == GEU
@@ -1909,7 +1919,7 @@ noce_get_alt_condition (struct noce_if_info *if_info,
rtx target,
}
cond = canonicalize_condition (if_info->jump, cond, reverse,
- earliest, target, false, true);
+ earliest, target, HAVE_cbranchcc4, true);
if (! cond || ! reg_mentioned_p (target, cond))
return NULL;
@@ -2401,7 +2411,7 @@ noce_get_condition (rtx_insn *jump, rtx_insn
**earliest, bool then_else_reversed
/* Otherwise, fall back on canonicalize_condition to do the dirty
work of manipulating MODE_CC values and COMPARE rtx codes. */
tmp = canonicalize_condition (jump, cond, reverse, earliest,
- NULL_RTX, false, true);
+ NULL_RTX, HAVE_cbranchcc4, true);
/* We don't handle side-effects in the condition, like handling
REG_INC notes and making sure no duplicate conditions are emitted. */
