[Bug target/66731] New: vnmul, fnmul patterns incorrect for -frounding-math

[Bug target/66731] New: vnmul, fnmul patterns incorrect for -frounding-math

[jsm28 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66731

            Bug ID: 66731
           Summary: vnmul, fnmul patterns incorrect for -frounding-math
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jsm28 at gcc dot gnu.org
  Target Milestone: ---
            Target: arm*-*-* aarch64*-*-*

config/arm/vfp.md has patterns:

(define_insn "*mulsf3negsf_vfp"
  [(set (match_operand:SF                  0 "s_register_operand" "=t")
        (mult:SF (neg:SF (match_operand:SF 1 "s_register_operand" "t"))
                 (match_operand:SF         2 "s_register_operand" "t")))]
  "TARGET_32BIT && TARGET_HARD_FLOAT && TARGET_VFP"
  "vnmul%?.f32\\t%0, %1, %2"
  [(set_attr "predicable" "yes")
   (set_attr "predicable_short_it" "no")
   (set_attr "type" "fmuls")]
)

(define_insn "*muldf3negdf_vfp"
  [(set (match_operand:DF                  0 "s_register_operand" "=w")
        (mult:DF (neg:DF (match_operand:DF 1 "s_register_operand" "w"))
                 (match_operand:DF         2 "s_register_operand" "w")))]
  "TARGET_32BIT && TARGET_HARD_FLOAT && TARGET_VFP_DOUBLE"
  "vnmul%?.f64\\t%P0, %P1, %P2"
  [(set_attr "predicable" "yes")
   (set_attr "predicable_short_it" "no")
   (set_attr "type" "fmuld")]
)

These describe the vnmul instruction as (-a) * b.  It's actually -(a * b).  The
two are different in round-upwards and round-downwards modes.  This is
resulting in miscompilation of tgamma from current glibc git (which uses (-a) *
b, expecting that actual multiplication), and consequent test failures.  On
inspection, AArch64 fnmul is similarly misdescribed, although I haven't done
any testing there.

[Bug target/66731] vnmul, fnmul patterns incorrect for -frounding-math

[nsz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66731

--- Comment #1 from nsz at gcc dot gnu.org ---
Author: nsz
Date: Mon Jul  6 11:00:03 2015
New Revision: 225450

URL: https://gcc.gnu.org/viewcvs?rev=225450&root=gcc&view=rev
Log:
[AArch64] PR target/66731 Fix fnmul insn with -frounding-math

gcc/Changelog:

2015-07-03  Szabolcs Nagy  <szabolcs.nagy@arm.com>

        PR target/66731
        * config/aarch64/aarch64.md (fnmul<mode>3): Handle -frounding-math.

gcc/testsuite/Changelog:

2015-07-03  Szabolcs Nagy  <szabolcs.nagy@arm.com>

        * gcc.target/aarch64/fnmul-1.c: New.
        * gcc.target/aarch64/fnmul-2.c: New.
        * gcc.target/aarch64/fnmul-3.c: New.
        * gcc.target/aarch64/fnmul-4.c: New.


Added:
    trunk/gcc/testsuite/gcc.target/aarch64/fnmul-1.c
    trunk/gcc/testsuite/gcc.target/aarch64/fnmul-2.c
    trunk/gcc/testsuite/gcc.target/aarch64/fnmul-3.c
    trunk/gcc/testsuite/gcc.target/aarch64/fnmul-4.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/aarch64/aarch64.md
    trunk/gcc/testsuite/ChangeLog

[Bug target/66731] vnmul, fnmul patterns incorrect for -frounding-math

[nsz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66731

--- Comment #2 from nsz at gcc dot gnu.org ---
Author: nsz
Date: Wed Jul 15 09:03:15 2015
New Revision: 225810

URL: https://gcc.gnu.org/viewcvs?rev=225810&root=gcc&view=rev
Log:
Add missing PR target/66731 to gcc/testsuite/Changelog

Modified:
    trunk/gcc/testsuite/ChangeLog

[Bug target/66731] vnmul, fnmul patterns incorrect for -frounding-math

[nsz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66731

--- Comment #4 from nsz at gcc dot gnu.org ---
Author: nsz
Date: Mon Aug  3 11:12:00 2015
New Revision: 226496

URL: https://gcc.gnu.org/viewcvs?rev=226496&root=gcc&view=rev
Log:
[ARM] PR target/66731 Fix vnmul insn with -frounding-math

gcc:

        PR target/66731
        * config/arm/vfp.md (negmuldf3_vfp): Add new pattern.
        (negmulsf3_vfp): Likewise.
        (muldf3negdf_vfp): Disable for -frounding-math.
        (mulsf3negsf_vfp): Likewise.
        * config/arm/arm.c (arm_new_rtx_costs): Fix NEG cost for VNMUL,
        fix MULT cost with -frounding-math.

gcc/testsuite:

        PR target/66731
        * gcc.target/arm/vnmul-1.c: New.
        * gcc.target/arm/vnmul-2.c: New.
        * gcc.target/arm/vnmul-3.c: New.
        * gcc.target/arm/vnmul-4.c: New.


Added:
    trunk/gcc/testsuite/gcc.target/arm/vnmul-1.c
    trunk/gcc/testsuite/gcc.target/arm/vnmul-2.c
    trunk/gcc/testsuite/gcc.target/arm/vnmul-3.c
    trunk/gcc/testsuite/gcc.target/arm/vnmul-4.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/arm/arm.c
    trunk/gcc/config/arm/vfp.md
    trunk/gcc/testsuite/ChangeLog

[Bug target/66731] vnmul, fnmul patterns incorrect for -frounding-math

[nsz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66731

--- Comment #5 from nsz at gcc dot gnu.org ---
Author: nsz
Date: Mon Aug  3 14:27:43 2015
New Revision: 226507

URL: https://gcc.gnu.org/viewcvs?rev=226507&root=gcc&view=rev
Log:
Backport form mainline r226496.

gcc:

        Backport form mainline r226496.
        2015-08-03  Szabolcs Nagy  <szabolcs.nagy@arm.com>

        PR target/66731
        * config/arm/vfp.md (negmuldf3_vfp): Add new pattern.
        (negmulsf3_vfp): Likewise.
        (muldf3negdf_vfp): Disable for -frounding-math.
        (mulsf3negsf_vfp): Likewise.
        * config/arm/arm.c (arm_new_rtx_costs): Fix NEG cost for VNMUL,
        fix MULT cost with -frounding-math.

gcc/testsuite:

        Backport form mainline r226496.
        2015-08-03  Szabolcs Nagy  <szabolcs.nagy@arm.com>

        PR target/66731
        * gcc.target/arm/vnmul-1.c: New.
        * gcc.target/arm/vnmul-2.c: New.
        * gcc.target/arm/vnmul-3.c: New.
        * gcc.target/arm/vnmul-4.c: New.


Added:
    branches/gcc-5-branch/gcc/testsuite/gcc.target/arm/vnmul-1.c
    branches/gcc-5-branch/gcc/testsuite/gcc.target/arm/vnmul-2.c
    branches/gcc-5-branch/gcc/testsuite/gcc.target/arm/vnmul-3.c
    branches/gcc-5-branch/gcc/testsuite/gcc.target/arm/vnmul-4.c
Modified:
    branches/gcc-5-branch/gcc/ChangeLog
    branches/gcc-5-branch/gcc/config/arm/arm.c
    branches/gcc-5-branch/gcc/config/arm/vfp.md
    branches/gcc-5-branch/gcc/testsuite/ChangeLog

[Bug target/66731] vnmul, fnmul patterns incorrect for -frounding-math

[nsz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66731

--- Comment #7 from nsz at gcc dot gnu.org ---
Author: nsz
Date: Tue Aug  4 16:22:32 2015
New Revision: 226586

URL: https://gcc.gnu.org/viewcvs?rev=226586&root=gcc&view=rev
Log:
[AArch64] PR target/66731 Fix fnmul insn with -frounding-math (rtx costs)

2015-08-04  Szabolcs Nagy  <szabolcs.nagy@arm.com>

        PR target/66731
        * config/aarch64/aarch64.c (aarch64_rtx_costs): Fix NEG cost for FNMUL.
        (aarch64_rtx_mult_cost): Fix MULT cost with -frounding-math.


Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/aarch64/aarch64.c

[Bug target/66731] vnmul, fnmul patterns incorrect for -frounding-math

[nsz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66731

--- Comment #8 from nsz at gcc dot gnu.org ---
Author: nsz
Date: Tue Aug  4 16:43:46 2015
New Revision: 226587

URL: https://gcc.gnu.org/viewcvs?rev=226587&root=gcc&view=rev
Log:
gcc:

        Backport from mainline:
        2015-08-04  Szabolcs Nagy  <szabolcs.nagy@arm.com>

        PR target/66731
        * config/aarch64/aarch64.c (aarch64_rtx_costs): Fix NEG cost for FNMUL.
        (aarch64_rtx_mult_cost): Fix MULT cost with -frounding-math.

        2015-07-06  Szabolcs Nagy  <szabolcs.nagy@arm.com>

        PR target/66731
        * config/aarch64/aarch64.md (fnmul<mode>3): Handle -frounding-math.

gcc/testsuite:

        Backport from mainline r225450:
        2015-07-06  Szabolcs Nagy  <szabolcs.nagy@arm.com>

        PR target/66731
        * gcc.target/aarch64/fnmul-1.c: New.
        * gcc.target/aarch64/fnmul-2.c: New.
        * gcc.target/aarch64/fnmul-3.c: New.
        * gcc.target/aarch64/fnmul-4.c: New.


Added:
    branches/gcc-5-branch/gcc/testsuite/gcc.target/aarch64/fnmul-1.c
    branches/gcc-5-branch/gcc/testsuite/gcc.target/aarch64/fnmul-2.c
    branches/gcc-5-branch/gcc/testsuite/gcc.target/aarch64/fnmul-3.c
    branches/gcc-5-branch/gcc/testsuite/gcc.target/aarch64/fnmul-4.c
Modified:
    branches/gcc-5-branch/gcc/ChangeLog
    branches/gcc-5-branch/gcc/config/aarch64/aarch64.c
    branches/gcc-5-branch/gcc/config/aarch64/aarch64.md
    branches/gcc-5-branch/gcc/testsuite/ChangeLog

[Bug target/66731] vnmul, fnmul patterns incorrect for -frounding-math

[nsz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66731

--- Comment #10 from nsz at gcc dot gnu.org ---
Author: nsz
Date: Tue Aug  4 17:42:05 2015
New Revision: 226592

URL: https://gcc.gnu.org/viewcvs?rev=226592&root=gcc&view=rev
Log:
gcc:
        Backport from mainline:
        2015-07-06  Szabolcs Nagy  <szabolcs.nagy@arm.com>

        PR target/66731
        * config/aarch64/aarch64.md (fnmul<mode>3): Handle -frounding-math.

gcc/testsuite:

        Backport from mainline r225450:
        2015-07-06  Szabolcs Nagy  <szabolcs.nagy@arm.com>

        PR target/66731
        * gcc.target/aarch64/fnmul-1.c: New.
        * gcc.target/aarch64/fnmul-2.c: New.
        * gcc.target/aarch64/fnmul-3.c: New.
        * gcc.target/aarch64/fnmul-4.c: New.


Added:
    branches/gcc-4_9-branch/gcc/testsuite/gcc.target/aarch64/fnmul-1.c
    branches/gcc-4_9-branch/gcc/testsuite/gcc.target/aarch64/fnmul-2.c
    branches/gcc-4_9-branch/gcc/testsuite/gcc.target/aarch64/fnmul-3.c
    branches/gcc-4_9-branch/gcc/testsuite/gcc.target/aarch64/fnmul-4.c
Modified:
    branches/gcc-4_9-branch/gcc/ChangeLog
    branches/gcc-4_9-branch/gcc/config/aarch64/aarch64.md
    branches/gcc-4_9-branch/gcc/testsuite/ChangeLog

[Bug target/66731] vnmul, fnmul patterns incorrect for -frounding-math

[nsz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66731

nsz at gcc dot gnu.org changed:

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

--- Comment #11 from nsz at gcc dot gnu.org ---
both arm and aarch64 should be fixed now (fix is backported to 4.9 and 5
branches)

[Bug target/66731] vnmul, fnmul patterns incorrect for -frounding-math

[ramana at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66731

Ramana Radhakrishnan <ramana at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.9.4

--- Comment #12 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
Fixed for 4.9.4