[Bug math/16449] New: S/390 Missing exceptions with llrint

[Bug math/16449] New: S/390 Missing exceptions with llrint

[krebbel1 at de dot ibm.com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16449

            Bug ID: 16449
           Summary: S/390 Missing exceptions with llrint
           Product: glibc
           Version: 2.19
            Status: NEW
          Severity: normal
          Priority: P2
         Component: math
          Assignee: unassigned at sourceware dot org
          Reporter: krebbel1 at de dot ibm.com

gcc version 4.9.0 20140109 (experimental) [trunk revision 206459] (GCC)

31 bit zarch

glibc testcase test-float:
testing float (without inline functions)
Failure: llrint (inf): Exception "Invalid operation" not set
Failure: llrint (-inf): Exception "Invalid operation" not set
Failure: llrint (qNaN): Exception "Invalid operation" not set
Failure: llrint_tonearest (inf): Exception "Invalid operation" not set
Failure: llrint_tonearest (-inf): Exception "Invalid operation" not set
Failure: llrint_tonearest (qNaN): Exception "Invalid operation" not set
Failure: llrint_towardzero (inf): Exception "Invalid operation" not set
Failure: llrint_towardzero (-inf): Exception "Invalid operation" not set
Failure: llrint_towardzero (qNaN): Exception "Invalid operation" not set
Failure: llrint_downward (inf): Exception "Invalid operation" not set
Failure: llrint_downward (-inf): Exception "Invalid operation" not set
Failure: llrint_downward (qNaN): Exception "Invalid operation" not set
Failure: llrint_upward (inf): Exception "Invalid operation" not set
Failure: llrint_upward (-inf): Exception "Invalid operation" not set
Failure: llrint_upward (qNaN): Exception "Invalid operation" not set
Failure: llround (inf): Exception "Invalid operation" not set
Failure: llround (-inf): Exception "Invalid operation" not set
Failure: llround (qNaN): Exception "Invalid operation" not set

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[Bug math/16449] S/390 Missing exceptions with llrint

[krebbel1 at de dot ibm.com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16449

Andreas Krebbel <krebbel1 at de dot ibm.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |s390-ibm-linux
               Host|                            |s390-ibm-linux
              Build|                            |s390-ibm-linux

--- Comment #1 from Andreas Krebbel <krebbel1 at de dot ibm.com> ---
Same happens with double and ldouble

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[Bug math/16449] S/390 Missing exceptions with llrint

[joseph at codesourcery dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=16449

--- Comment #2 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
Likely to be a bug in the s390-specific libgcc functions 
(libgcc/config/s390/32), since llrint handles out-of-range values by a 
simple cast, which is supposed to raise INVALID.

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[Bug math/16449] S/390 Missing exceptions with llrint

[stli at linux dot vnet.ibm.com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16449

stli at linux dot vnet.ibm.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |stli at linux dot vnet.ibm.com

--- Comment #3 from stli at linux dot vnet.ibm.com ---
the cast from float to long long is handled by a call to libgcc __fixsfdi
function. This function in (libgcc/config/s390/32) does not raise the INVALID
exception.
According to c99 standard the cast is a conversion from float to integer and
"If the value of the integral part cannot be represented by the integer type,
the behavior is undefined."
Is it correct to rely on the simple cast in glibc?

In case of lrint, the cast to long is done via hardware instruction, which sets
the INVALID flag. The same happens on 64 bit zarch.

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[Bug math/16449] S/390 Missing exceptions with llrint

[joseph at codesourcery dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=16449

--- Comment #4 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
On Tue, 28 Jan 2014, stli at linux dot vnet.ibm.com wrote:

> the cast from float to long long is handled by a call to libgcc __fixsfdi
> function. This function in (libgcc/config/s390/32) does not raise the INVALID
> exception.
> According to c99 standard the cast is a conversion from float to integer and
> "If the value of the integral part cannot be represented by the integer type,
> the behavior is undefined."
> Is it correct to rely on the simple cast in glibc?

Annex F changes this from undefined to unspecified value plus INVALID 
exception (F.4 in C99).

There may well be a case for working around GCC deficiencies in this area 
in glibc (conditional on architecture and GCC version needing it) - such 
problems apply to several architectures, with the details of what needs 
fixing varying from architecture to architecture - but I'd also encourage 
reporting libgcc bugs found, and fixing them if possible.

(Properly supporting Annex F in GCC is a large amount of work - but I'd 
like to see it done, and indeed the more recent under-development C 
bindings for IEEE 754-2008.  This particular issue is one of the bits that 
could be addressed by a reasonably small self-contained patch.)

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[Bug math/16449] [s390] S/390 Missing exceptions with llrint

[jsm28 at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=16449

Joseph Myers <jsm28 at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|S/390 Missing exceptions    |[s390] S/390 Missing
                   |with llrint                 |exceptions with llrint

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[Bug math/16449] [s390] S/390 Missing exceptions with llrint

[krebbel1 at de dot ibm.com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16449

Andreas Krebbel <krebbel1 at de dot ibm.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #5 from Andreas Krebbel <krebbel1 at de dot ibm.com> ---
Fixed in GCC with:
http://gcc.gnu.org/ml/gcc-patches/2014-02/msg00399.html

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[Bug math/16449] [s390] S/390 Missing exceptions with llrint

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16449

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
              Flags|                            |security-

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