[Patch ARM] Fix PR45070 - Miscompiled c++ class with packed attribute on ARM with -Os optimizations

[Mikael Pettersson]

Ian Bolton writes:
 > This patch fixes PR45070, and provides a regression test for it.
 > 
 > The bug was caused by a faulty assumption that arm_size_return_regs() did
 > not return values in the range 1-3.  This meant that the return value for
 > a packed struct containing a short could sometimes be clobbered for -Os,
 > as shown by the supplied regression test.
...
 > --- /dev/null	2010-05-18 17:29:48.296470258 +0100
 > +++ gcc/testsuite/gcc.target/arm/pr45070.c	2010-08-11 11:43:32.187695894 +0100
 > @@ -0,0 +1,54 @@
 > +/* PR45070 */
 > +/* { dg-do run { target arm*-*-* }  } */
 > +/* { dg-options "-mcpu=cortex-a8 -Os"  } */

The test case options appear to be incorrect.

1. You'd end up trying to execute cortex-a8 specific object
   code on non cortex-a8 compatible CPUs.
2. The bug and the test case are not specific to cortex-a8.
   In the PR trail you see at least two people confirming the
   bug on plain old armv5te.

The test shouldn't need any option except "-Os".

/Mikael