Please backport some GCC 13 build fixes

Please backport some GCC 13 build fixes

[WANG Xuerui]

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Hi,

As it's entirely possible for users to pair the upcoming gcc-13 with one 
of the older glibc versions, it may be prudent to backport at least the 
following commits so builds won't fail in such cases:

  * 3e5760fcb4 ("Update _FloatN header support for C++ in GCC 13")
  * ba70f69598 ("Fix iseqsig for _FloatN and _FloatNx in C++ with GCC 13")
  * f66780ba46 ("Fix build with GCC 13 _FloatN, _FloatNx built-in
    functions")

Thanks!

(P.S. I don't have glibc commit rights so someone else would have to 
commit for me. Sorry about that.)

-- 
WANG Xuerui
xen0n@gentoo.org
Gentoo Linux developer
PGP: 7C52 19E3 26A0 7311 3EA3 8806 C01F 7214 BC93 1414


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Re: Please backport some GCC 13 build fixes

[Andreas K. Huettel]

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>   * 3e5760fcb4 ("Update _FloatN header support for C++ in GCC 13")
>   * ba70f69598 ("Fix iseqsig for _FloatN and _FloatNx in C++ with GCC 13")
>   * f66780ba46 ("Fix build with GCC 13 _FloatN, _FloatNx built-in
>     functions")

FWIW, I added these three commits to our 2.36 and got some FP test failures
requiring distinct changes in ulps.

Hardware / software: 
Linux pinacolada 5.19.17-gentoo #1 SMP PREEMPT_DYNAMIC Sun Nov 6 20:29:37 CET 2022 x86_64 Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz GenuineIntel GNU/Linux
gcc (Gentoo 11.3.0 p7) 11.3.0

Failure summary:
FAIL: math/test-double-j0
FAIL: math/test-float-ctan
FAIL: math/test-float-j1
FAIL: math/test-float-y0
FAIL: math/test-float-y1
FAIL: math/test-float32-ctan
FAIL: math/test-float32-j1
FAIL: math/test-float32-y0
FAIL: math/test-float32-y1
FAIL: math/test-float32x-j0
FAIL: math/test-float64-j0

Patch produced by regen-ulps:

diff --git a/sysdeps/i386/i686/fpu/multiarch/libm-test-ulps b/sysdeps/i386/i686/fpu/multiarch/libm-test-ulps
index 284e3fa275..8705a7822c 100644
--- a/sysdeps/i386/i686/fpu/multiarch/libm-test-ulps
+++ b/sysdeps/i386/i686/fpu/multiarch/libm-test-ulps
@@ -1027,7 +1027,7 @@ ldouble: 3
 
 Function: Imaginary part of "ctan_upward":
 double: 2
-float: 1
+float: 2
 float128: 5
 ldouble: 3
 
@@ -1260,13 +1260,13 @@ float128: 2
 ldouble: 8
 
 Function: "j0_downward":
-double: 5
+double: 6
 float: 9
 float128: 9
 ldouble: 6
 
 Function: "j0_towardzero":
-double: 6
+double: 7
 float: 9
 float128: 9
 ldouble: 6
@@ -1285,13 +1285,13 @@ ldouble: 9
 
 Function: "j1_downward":
 double: 5
-float: 6
+float: 8
 float128: 4
 ldouble: 4
 
 Function: "j1_towardzero":
 double: 4
-float: 6
+float: 8
 float128: 4
 ldouble: 4
 
@@ -1617,7 +1617,7 @@ ldouble: 5
 
 Function: "y0_towardzero":
 double: 4
-float: 4
+float: 8
 float128: 3
 ldouble: 8
 
@@ -1641,7 +1641,7 @@ ldouble: 7
 
 Function: "y1_towardzero":
 double: 3
-float: 4
+float: 9
 float128: 6
 ldouble: 5
 


-- 
Andreas K. Hüttel
dilfridge@gentoo.org
Gentoo Linux developer
(council, toolchain, base-system, perl, libreoffice)

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Re: Please backport some GCC 13 build fixes

[Joseph Myers]

On Sat, 19 Nov 2022, Andreas K. Huettel via Libc-stable wrote:

> >   * 3e5760fcb4 ("Update _FloatN header support for C++ in GCC 13")
> >   * ba70f69598 ("Fix iseqsig for _FloatN and _FloatNx in C++ with GCC 13")
> >   * f66780ba46 ("Fix build with GCC 13 _FloatN, _FloatNx built-in
> >     functions")
> 
> FWIW, I added these three commits to our 2.36 and got some FP test failures
> requiring distinct changes in ulps.

These aren't meant to change the code generated for glibc (with any given 
GCC version that worked for building glibc before those changes, so GCC 12 
or before) at all, so it would be a good idea to investigate why the 
generated code changed.

-- 
Joseph S. Myers
joseph@codesourcery.com

[Disregard my previous mail] Re: Please backport some GCC 13 build fixes

[Andreas K. Huettel]

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Am Montag, 21. November 2022, 21:37:18 CET schrieb Joseph Myers:
> On Sat, 19 Nov 2022, Andreas K. Huettel via Libc-stable wrote:
> 
> > >   * 3e5760fcb4 ("Update _FloatN header support for C++ in GCC 13")
> > >   * ba70f69598 ("Fix iseqsig for _FloatN and _FloatNx in C++ with GCC 13")
> > >   * f66780ba46 ("Fix build with GCC 13 _FloatN, _FloatNx built-in
> > >     functions")
> > 
> > FWIW, I added these three commits to our 2.36 and got some FP test failures
> > requiring distinct changes in ulps.
> 
> These aren't meant to change the code generated for glibc (with any given 
> GCC version that worked for building glibc before those changes, so GCC 12 
> or before) at all, so it would be a good idea to investigate why the 
> generated code changed.

My apologies; this was *not* caused by the three commits listed above.
So, from my point of view there are no problems at all with backporting them.

The changes which broke the tests must have crept into the/our release branch
earlier. Searching.

-- 
Andreas K. Hüttel
dilfridge@gentoo.org
Gentoo Linux developer
(council, toolchain, base-system, perl, libreoffice)

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