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From: "jay.krell at cornell dot edu" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/56361] New: assertion failure passing structs w/o fields by value on sparc64
Date: Sun, 17 Feb 2013 10:11:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56361

             Bug #: 56361
           Summary: assertion failure passing structs w/o fields by value
                    on sparc64
    Classification: Unclassified
           Product: gcc
           Version: 4.7.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jay.krell@cornell.edu


We have a strange front end.
It declares structs with size but no fields.
It actually works..except sometimes for SPARC64.


We have a function that passes a few structs by value.
They are 12 bytes each.



4.7.2/config/sparc/sparc.c:
static rtx
function_arg_record_value (const_tree type, enum machine_mode mode,
               int slotno, int named, int regbase)
.
.
.

      else
    {
      /* ??? C++ has structures with no fields, and yet a size.  Give up
         for now and pass everything back in integer registers.  */
      nregs = (typesize + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
    }
      if (nregs + slotno > SPARC_INT_ARG_MAX)
    nregs = SPARC_INT_ARG_MAX - slotno;
    }
  gcc_assert (nregs != 0);



SPARC_INT_ARG_MAX == 6
nregs = 2
slotno = 6
so then nregs = 0
and the assert fails


I think it should say:
  gcc_assert (nregs != 0 || parms.stack);