[U-Boot] [PATCH] powerpc/mpc85xx:Add GCC flag -fno-delete-null-pointer-checks

[Tom Rini]

On Tue, Jun 30, 2015 at 08:58:26AM -0600, Simon Glass wrote:
> Hi,
> 
> On 29 June 2015 at 22:18, Kushwaha Prabhakar <prabhakar at freescale.com> wrote:
> > Hi Simon, Tom,
> >
> > -fdelete-null-pointer-checks flag controls global dataflow analyses and  eliminate useless checks for null pointers; It assume that if a pointer is  checked after it has already been dereferenced, it cannot be null.  This flag is enabled by default.
> >  gcc v4.9 has more optimizations added to this option. Hence it is very  aggressive with GCC v4.9 series. It is also well documented in the GCC v4.9 release notes:
> > https://gcc.gnu.org/gcc-4.9/porting_to.html
> >
> > There is possibility after moving to gcc-4.9 some platform may/may not work properly.
> > I tested this patch for freescale powerpc platforms.
> > But It may needs be taken care by all architecture like ARM, powerpc. If this is the case; this flag should be in top level Makefile (not sure)
> >
> 
> I suspect a top-level option would be best, perhaps near this one in Makefile:
> 
> KBUILD_CFLAGS += $(call cc-option,-fno-stack-protector)

I also agree with Scott and Simon, default, top level, using cc-option
just like the Linux kernel please, thanks!

-- 
Tom
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