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* [Bug c/63673] New: VSX intrinsic vec_vsx_ld fails to compile with double, maps to wrong instructions with float
@ 2014-10-29  7:22 markos at freevec dot org
  2014-10-29  7:23 ` [Bug c/63673] " markos at freevec dot org
                   ` (7 more replies)
  0 siblings, 8 replies; 9+ messages in thread
From: markos at freevec dot org @ 2014-10-29  7:22 UTC (permalink / raw)
  To: gcc-bugs

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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63673

            Bug ID: 63673
           Summary: VSX intrinsic vec_vsx_ld fails to compile with double,
                    maps to wrong instructions with float
           Product: gcc
           Version: 4.9.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: markos at freevec dot org

Created attachment 33836
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33836&action=edit
failing to compile testcase for vec_vsx_ld using doubles

These are actually two issues, but I'm filing a single bug report as it looks
like they are related.

First the build error, I've created a small failing testcase (also attached):

--
#include <altivec.h>

int main() {
        double __attribute__((aligned(16))) d[4] = {0.0, 1.0, 2.0, 3.0 };

        vector double v = vec_vsx_ld(8, d); // should load {1.0, 2.0}
}
--

This fails to compile under Debian gcc (4.9.1-19), with the following error:

$ gcc vec_vsx_ld_fail.c -c
vec_vsx_ld_fail.c: In function ‘main’:
vec_vsx_ld_fail.c:6:2: error: invalid parameter combination for AltiVec
intrinsic
  vector double v = vec_vsx_ld(4, d); // should load {1.0, 2.0}

Casting d to (float *) makes it compile, but vec_vsx_ld intrinsic definitely
should handle double parameters, so I think this is a bug.

Now the second problem, a similar testcase for float (also attached):
--
#include <altivec.h>

int main() {
        float __attribute__((aligned(16))) f[8] = {0.0, 1.0, 2.0, 3.0, 4.0,
5.0, 6.0, 7.0 };

        vector float v = vec_vsx_ld(4, f); // should load {1.0, 2.0, 3.0, 4.0}
}
--

This does compile, but the asm output uses the lxvd2x asm instruction, when
according the the ISA, lxvw4x should be used -at least according to my
understanding (page 359, Power ISA 2.07). Asm output also attached.
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From: "andi-gcc at firstfloor dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/63672] New: xbegin/xend/xabort missing memory barriers
Date: Wed, 29 Oct 2014 07:22:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idc672

            Bug ID: 63672
           Summary: xbegin/xend/xabort missing memory barriers
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: andi-gcc at firstfloor dot org

Created attachment 33835
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id3835&actioníit
proposed patch adding barriers

No test case currently, but we got a report that the builtins for x86 RTM
xbegin/xend/xabort are missing implicit memory barriers. This can cause code to
be moved outside the critical sections, breaking the program.


^ permalink raw reply	[flat|nested] 9+ messages in thread
end of thread, other threads:[~2014-11-21 15:41 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-10-29  7:22 [Bug c/63673] New: VSX intrinsic vec_vsx_ld fails to compile with double, maps to wrong instructions with float markos at freevec dot org
2014-10-29  7:23 ` [Bug c/63673] " markos at freevec dot org
2014-10-29  8:00 ` markos at freevec dot org
2014-11-20 21:20 ` [Bug target/63673] " wschmidt at gcc dot gnu.org
2014-11-20 21:28 ` wschmidt at gcc dot gnu.org
2014-11-21 10:03 ` markos at freevec dot org
2014-11-21 15:38 ` wschmidt at gcc dot gnu.org
2014-11-21 15:39 ` wschmidt at gcc dot gnu.org
2014-11-21 15:41 ` wschmidt at gcc dot gnu.org

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