[Bug target/47312] New: [4.6 Regression] ICE: in expand_ternary_op, at optabs.c:656 with -flto -mno-sse -mxop and __builtin_fmaf()

[Bug target/47312] New: [4.6 Regression] ICE: in expand_ternary_op, at optabs.c:656 with -flto -mno-sse -mxop and __builtin_fmaf()

[zsojka at seznam dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47312

           Summary: [4.6 Regression] ICE: in expand_ternary_op, at
                    optabs.c:656 with -flto -mno-sse -mxop and
                    __builtin_fmaf()
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: zsojka@seznam.cz
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu


------ testcase.c -------
int main ()
{
  return __builtin_fmaf(1e+38F, 1e+38F, 0);
}
-------------------------

Compiler output:
$ gcc -O -flto -mno-sse -mxop testcase.c 
In file included from testcase.c:1:0,
                 from :0:
testcase.c: In function 'main':
testcase.c:3:24: internal compiler error: in expand_ternary_op, at optabs.c:656
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
lto-wrapper:
/mnt/svn/gcc-trunk/binary-168843-lto-fortran-checking-yes-rtl-df/bin/gcc
returned 1 exit status
collect2: lto-wrapper returned 1 exit status

Tested revisions:
r168843 - crash
4.5 r168785 - OK

[Bug target/47312] [4.6 Regression] ICE: in expand_ternary_op, at optabs.c:656 with -flto -mno-sse -mxop and __builtin_fmaf()

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47312

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2011.01.17 13:29:34
   Target Milestone|---                         |4.6.0
     Ever Confirmed|0                           |1

[Bug target/47312] [4.6 Regression] ICE: in expand_ternary_op, at optabs.c:656 with -flto -mno-sse -mxop and __builtin_fmaf()

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47312

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-01-17 15:46:52 UTC ---
With LTO, relying on FMA_EXPR being present in the IL only iff target supports
it is IMHO wrong, because using slightly different options between cc1 and lto1
can result in optab_handler (fma_optab, mode) == CODE_FOR_nothing even when
FMA_EXPR is present in the IL.  I'd say we should expand FMA_EXPR as
__builtin_fma in that case.  Richi, do you agree?

[Bug target/47312] [4.6 Regression] ICE: in expand_ternary_op, at optabs.c:656 with -flto -mno-sse -mxop and __builtin_fmaf()

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47312

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug target/47312] [4.6 Regression] ICE: in expand_ternary_op, at optabs.c:656 with -flto -mno-sse -mxop and __builtin_fmaf()

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47312

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-02-02 15:24:25 UTC ---
One possibility would be to only fold __builtin_fma* into FMA_EXPR after IPA
passes.

[Bug target/47312] [4.6 Regression] ICE: in expand_ternary_op, at optabs.c:656 with -flto -mno-sse -mxop and __builtin_fmaf()

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47312

--- Comment #3 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-02-02 15:30:51 UTC ---
(In reply to comment #2)
> One possibility would be to only fold __builtin_fma* into FMA_EXPR after IPA
> passes.

Expanding FMA_EXPR as __builtin_fma (thus, a libcall) as fallback sounds
safe.  We probably have similar issues for other builtins (consider
the generic vector lowering code for example).

Thus, in expr.c only dispatch to expand_ternary_op if there is an optab
available, else emit a libcall.

"Folding" back to __builtin_fma* sounds ugly.

[Bug target/47312] [4.6 Regression] ICE: in expand_ternary_op, at optabs.c:656 with -flto -mno-sse -mxop and __builtin_fmaf()

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47312

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-02-02 15:39:00 UTC ---
FMA_EXPR is created though not only just for __builtin_fma{,l,f} in the code,
but also for x * y + z when contracting.  Can expansion rely that this is
happening only after IPA passes?  Otherwise we could be creating fma,f,l} calls
in freestanding environments, or try create it say for __float128 where there
is no such builtin, etc.

[Bug target/47312] [4.6 Regression] ICE: in expand_ternary_op, at optabs.c:656 with -flto -mno-sse -mxop and __builtin_fmaf()

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47312

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-02-03 10:53:21 UTC ---
Author: jakub
Date: Thu Feb  3 10:53:19 2011
New Revision: 169786

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=169786
Log:
    PR target/47312
    * expr.c (expand_expr_real_2) <case FMA_EXPR>: If target doesn't expand
    fma, expand FMA_EXPR as fma{,f,l} call.

    * gcc.target/i386/pr47312.c: New test.

Added:
    trunk/gcc/testsuite/gcc.target/i386/pr47312.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/expr.c
    trunk/gcc/testsuite/ChangeLog

[Bug target/47312] [4.6 Regression] ICE: in expand_ternary_op, at optabs.c:656 with -flto -mno-sse -mxop and __builtin_fmaf()

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47312

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

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

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-02-03 11:00:11 UTC ---
Fixed.