* MIPS tests (nan-legacy.c and nans-legacy.c) failing
@ 2013-07-30 23:27 Steve Ellcey
2013-08-07 20:20 ` Richard Sandiford
0 siblings, 1 reply; 6+ messages in thread
From: Steve Ellcey @ 2013-07-30 23:27 UTC (permalink / raw)
To: macro; +Cc: gcc-patches
Maciej,
When I run two of your new tests in gcc.target/mips (nan-legacy.c and
nans-legacy.c), they are failing because my GCC is putting out
.word 4294967295
instead of
.word -1
like the test is expecting.
I believe they are equivalent (0xffffffff) but I am not sure what it
is about my targets (mips-mti-elf and mips-mti-linux-gnu) that would
make this different from yours. Should the tests be modified to allow
either output?
Steve Ellcey
sellcey@mips.com
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: MIPS tests (nan-legacy.c and nans-legacy.c) failing
2013-07-30 23:27 MIPS tests (nan-legacy.c and nans-legacy.c) failing Steve Ellcey
@ 2013-08-07 20:20 ` Richard Sandiford
2013-08-13 13:28 ` Maciej W. Rozycki
0 siblings, 1 reply; 6+ messages in thread
From: Richard Sandiford @ 2013-08-07 20:20 UTC (permalink / raw)
To: Steve Ellcey ; +Cc: macro, gcc-patches
"Steve Ellcey " <sellcey@mips.com> writes:
> Maciej,
>
> When I run two of your new tests in gcc.target/mips (nan-legacy.c and
> nans-legacy.c), they are failing because my GCC is putting out
>
> .word 4294967295
>
> instead of
>
> .word -1
>
> like the test is expecting.
>
> I believe they are equivalent (0xffffffff) but I am not sure what it
> is about my targets (mips-mti-elf and mips-mti-linux-gnu) that would
> make this different from yours. Should the tests be modified to allow
> either output?
Maciej, have you had chance to look at this yet?
Thanks,
Richard
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: MIPS tests (nan-legacy.c and nans-legacy.c) failing
2013-08-07 20:20 ` Richard Sandiford
@ 2013-08-13 13:28 ` Maciej W. Rozycki
2013-08-13 16:49 ` Steve Ellcey
2013-08-13 17:25 ` Richard Sandiford
0 siblings, 2 replies; 6+ messages in thread
From: Maciej W. Rozycki @ 2013-08-13 13:28 UTC (permalink / raw)
To: Richard Sandiford, Steve Ellcey; +Cc: gcc-patches
On Wed, 7 Aug 2013, Richard Sandiford wrote:
> > When I run two of your new tests in gcc.target/mips (nan-legacy.c and
> > nans-legacy.c), they are failing because my GCC is putting out
> >
> > .word 4294967295
> >
> > instead of
> >
> > .word -1
> >
> > like the test is expecting.
> >
> > I believe they are equivalent (0xffffffff) but I am not sure what it
> > is about my targets (mips-mti-elf and mips-mti-linux-gnu) that would
> > make this different from yours. Should the tests be modified to allow
> > either output?
>
> Maciej, have you had chance to look at this yet?
I've had a look now and that is related to the width of `long' on the
host -- encode_ieee_double returns its output 32-bit bit patterns in a
buffer of signed longs. The arithmetic value of these patterns therefore
depends on whether the width of `long' is 32 bits or wider.
Here, in the case of nan-legacy.c, we have:
image_hi <- 0x7ff7ffff
image_lo <- 0xffffffff
so the returned pair of long values will be:
2146959359, -1
on a host where the width of `long' is 32 bits and:
2146959359, 4294967295
on a host where the width of `long' is 64 bits. Then when supplied as the
argument to the assembly-language .word pseudo-op, the two sets of values
produce the same bit patterns in the object file produced.
It's not clear to me if this dependency on the width of `long' is a bug
or feature, but a path-of-least-resistance fix is as follows.
This has passed mips-linux-gnu regression testing on a 32-bit host, but I
can't regression-test a 64-bit host easily -- Steve, can you please verify
that this change indeed works for you? Richard, OK to apply assuming that
it does?
2013-08-13 Maciej W. Rozycki <macro@codesourcery.com>
gcc/testsuite/
* gcc.target/mips/nan-legacy.c: Accept 4294967295 as an
alternative to -1.
* gcc.target/mips/nans-legacy.c: Likewise.
Maciej
gcc-mips-nan2008-test-fix.diff
Index: gcc-fsf-trunk-quilt/gcc/testsuite/gcc.target/mips/nan-legacy.c
===================================================================
--- gcc-fsf-trunk-quilt.orig/gcc/testsuite/gcc.target/mips/nan-legacy.c 2013-08-13 14:18:50.008738612 +0100
+++ gcc-fsf-trunk-quilt/gcc/testsuite/gcc.target/mips/nan-legacy.c 2013-08-13 14:22:49.568772451 +0100
@@ -4,4 +4,4 @@
double d = __builtin_nan ("");
/* { dg-final { scan-assembler "\t\\.nan\tlegacy\n" } } */
-/* { dg-final { scan-assembler "\t\\.word\t2146959359\n\t\\.word\t-1\n" } } */
+/* { dg-final { scan-assembler "\t\\.word\t2146959359\n\t\\.word\t(?:-1|4294967295)\n" } } */
Index: gcc-fsf-trunk-quilt/gcc/testsuite/gcc.target/mips/nans-legacy.c
===================================================================
--- gcc-fsf-trunk-quilt.orig/gcc/testsuite/gcc.target/mips/nans-legacy.c 2013-08-13 14:18:50.008738612 +0100
+++ gcc-fsf-trunk-quilt/gcc/testsuite/gcc.target/mips/nans-legacy.c 2013-08-13 14:22:49.568772451 +0100
@@ -4,4 +4,4 @@
double ds = __builtin_nans ("");
/* { dg-final { scan-assembler "\t\\.nan\tlegacy\n" } } */
-/* { dg-final { scan-assembler "\t\\.word\t2147483647\n\t\\.word\t-1\n" } } */
+/* { dg-final { scan-assembler "\t\\.word\t2147483647\n\t\\.word\t(?:-1|4294967295)\n" } } */
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: MIPS tests (nan-legacy.c and nans-legacy.c) failing
2013-08-13 13:28 ` Maciej W. Rozycki
@ 2013-08-13 16:49 ` Steve Ellcey
2013-08-13 17:25 ` Richard Sandiford
1 sibling, 0 replies; 6+ messages in thread
From: Steve Ellcey @ 2013-08-13 16:49 UTC (permalink / raw)
To: Maciej W. Rozycki; +Cc: Richard Sandiford, gcc-patches
On Tue, 2013-08-13 at 14:28 +0100, Maciej W. Rozycki wrote:
> This has passed mips-linux-gnu regression testing on a 32-bit host, but I
> can't regression-test a 64-bit host easily -- Steve, can you please verify
> that this change indeed works for you? Richard, OK to apply assuming that
> it does?
Maciej, the patch does work for me.
Steve Ellcey
sellcey@mips.com
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: MIPS tests (nan-legacy.c and nans-legacy.c) failing
2013-08-13 13:28 ` Maciej W. Rozycki
2013-08-13 16:49 ` Steve Ellcey
@ 2013-08-13 17:25 ` Richard Sandiford
2013-08-13 21:53 ` Maciej W. Rozycki
1 sibling, 1 reply; 6+ messages in thread
From: Richard Sandiford @ 2013-08-13 17:25 UTC (permalink / raw)
To: Maciej W. Rozycki; +Cc: Steve Ellcey, gcc-patches
"Maciej W. Rozycki" <macro@codesourcery.com> writes:
> I've had a look now and that is related to the width of `long' on the
> host -- encode_ieee_double returns its output 32-bit bit patterns in a
> buffer of signed longs. The arithmetic value of these patterns therefore
> depends on whether the width of `long' is 32 bits or wider.
>
> Here, in the case of nan-legacy.c, we have:
>
> image_hi <- 0x7ff7ffff
> image_lo <- 0xffffffff
>
> so the returned pair of long values will be:
>
> 2146959359, -1
>
> on a host where the width of `long' is 32 bits and:
>
> 2146959359, 4294967295
>
> on a host where the width of `long' is 64 bits. Then when supplied as the
> argument to the assembly-language .word pseudo-op, the two sets of values
> produce the same bit patterns in the object file produced.
>
> It's not clear to me if this dependency on the width of `long' is a bug
> or feature, but a path-of-least-resistance fix is as follows.
IMO a bug. If we're sure 32 bits is enough then we should use "int".
If we're not sure we should use HOST_WIDE_INT. The only thing using
"long" is going to do is create this kind of weird host dependence.
I can't argue with the path of least resistance though.
> 2013-08-13 Maciej W. Rozycki <macro@codesourcery.com>
>
> gcc/testsuite/
> * gcc.target/mips/nan-legacy.c: Accept 4294967295 as an
> alternative to -1.
> * gcc.target/mips/nans-legacy.c: Likewise.
OK, thanks.
Richard
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: MIPS tests (nan-legacy.c and nans-legacy.c) failing
2013-08-13 17:25 ` Richard Sandiford
@ 2013-08-13 21:53 ` Maciej W. Rozycki
0 siblings, 0 replies; 6+ messages in thread
From: Maciej W. Rozycki @ 2013-08-13 21:53 UTC (permalink / raw)
To: Richard Sandiford; +Cc: Steve Ellcey, gcc-patches
On Tue, 13 Aug 2013, Richard Sandiford wrote:
> > I've had a look now and that is related to the width of `long' on the
> > host -- encode_ieee_double returns its output 32-bit bit patterns in a
> > buffer of signed longs. The arithmetic value of these patterns therefore
> > depends on whether the width of `long' is 32 bits or wider.
> >
> > Here, in the case of nan-legacy.c, we have:
> >
> > image_hi <- 0x7ff7ffff
> > image_lo <- 0xffffffff
> >
> > so the returned pair of long values will be:
> >
> > 2146959359, -1
> >
> > on a host where the width of `long' is 32 bits and:
> >
> > 2146959359, 4294967295
> >
> > on a host where the width of `long' is 64 bits. Then when supplied as the
> > argument to the assembly-language .word pseudo-op, the two sets of values
> > produce the same bit patterns in the object file produced.
> >
> > It's not clear to me if this dependency on the width of `long' is a bug
> > or feature, but a path-of-least-resistance fix is as follows.
>
> IMO a bug. If we're sure 32 bits is enough then we should use "int".
> If we're not sure we should use HOST_WIDE_INT. The only thing using
> "long" is going to do is create this kind of weird host dependence.
Since encode_ieee_double will always return 32-bit chunks I think these
days this should really use explicit `int32_t' rather than `long' or
trying to guess what `int' or HOST_WIDE_INT might be. The type can be
easily autoconf'ed if missing on pre-C99 hosts.
Of course all the real.c handlers would have to be reviewed and adjusted
accordingly, as would the callers, e.g. assemble_real in varasm.c which is
where the buffer in this particular case comes from (`data').
> > gcc/testsuite/
> > * gcc.target/mips/nan-legacy.c: Accept 4294967295 as an
> > alternative to -1.
> > * gcc.target/mips/nans-legacy.c: Likewise.
>
> OK, thanks.
Thanks for review, applied. Steve, thanks for verifying.
Maciej
^ permalink raw reply [flat|nested] 6+ messages in thread
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2013-07-30 23:27 MIPS tests (nan-legacy.c and nans-legacy.c) failing Steve Ellcey
2013-08-07 20:20 ` Richard Sandiford
2013-08-13 13:28 ` Maciej W. Rozycki
2013-08-13 16:49 ` Steve Ellcey
2013-08-13 17:25 ` Richard Sandiford
2013-08-13 21:53 ` Maciej W. Rozycki
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