[Bug middle-end/29683] New: Arg split between stack/regs can cause stack corruption

["jconner at apple dot com" <gcc-bugzilla at gcc dot gnu dot org>]

On targets which allow a function argument to be split between registers and
the stack, values can be corrupted by later function calls.

Specifically - this code:

~~~~~~~~~~

/* { dg-do run } */
/* { dg-options "-Os -fno-inline-functions" } */

void abort (void);

typedef struct {
  int x[7];
} agg7;

typedef struct {
  int mbr1;
  int mbr2;
} agg2;

int expected = 31415;
agg7 filler;

int GetConst (agg7 filler, agg2 split)
{
  return expected;
}

void VerifyValues (agg7 filler, int last_reg, int first_stack, int
second_stack)
{
  if (first_stack != 123 || second_stack != expected)
    abort ();
}

void RunTest (agg2 a)
{
  int result;

  result = GetConst (filler, a);
  VerifyValues (filler, 0, a.mbr1, result);
}

int main(void)
{
  agg2 result = {123, 456};
  RunTest (result);
  return 0;
}

~~~~~~~~~~

compiled with "gcc -O1" incorrectly aborts.


-- 
           Summary: Arg split between stack/regs can cause stack corruption
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jconner at apple dot com
  GCC host triplet: powerpc-apple-darwin8
GCC target triplet: powerpc-apple-darwin8


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29683