Re: [Xen-devel] [PATCH ARM v7 13/13] mini-os: fixed compiling with debug=n

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Fri, 2014-08-08 at 16:47 +0100, Thomas Leonard wrote:
> Without -fno-tree-loop-distribute-patterns, gcc -O3 recognises that our
> "memset" is doing a memset operation and tries to make it call the
> standard "memset", creating a loop.

As in __builtin_memset or some such? Isn't there are -nostdthings we
could/should use? -fno-tree-loop... seems a bit abstracted from the
affect and it's not impossible that different gcc would still do this
same thing in the future under some other optimisation.

> The change to fdt_ro.c is to avoid a compiler warning.

Ah, here it is for real ;-)

> 
> Signed-off-by: Thomas Leonard <talex5@xxxxxxxxx>
> ---
>  extras/mini-os/minios.mk   | 2 +-
>  xen/common/libfdt/fdt_ro.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/extras/mini-os/minios.mk b/extras/mini-os/minios.mk
> index 20ba64b..3e881e4 100644
> --- a/extras/mini-os/minios.mk
> +++ b/extras/mini-os/minios.mk
> @@ -23,7 +23,7 @@ DEF_CFLAGS += -g
>  #DEF_CFLAGS += -DGNT_DEBUG
>  #DEF_CFLAGS += -DGNTMAP_DEBUG
>  else
> -DEF_CFLAGS += -O3
> +DEF_CFLAGS += -O3 -fno-tree-loop-distribute-patterns
>  endif
>  
>  # Make the headers define our internal stuff
> diff --git a/xen/common/libfdt/fdt_ro.c b/xen/common/libfdt/fdt_ro.c
> index 02b6d68..a34c6d6 100644
> --- a/xen/common/libfdt/fdt_ro.c
> +++ b/xen/common/libfdt/fdt_ro.c
> @@ -444,7 +444,7 @@ int fdt_supernode_atdepth_offset(const void *fdt, int 
> nodeoffset,
>  
>  int fdt_node_depth(const void *fdt, int nodeoffset)
>  {
> -     int nodedepth;
> +     int nodedepth = -1;
>       int err;
>  
>       err = fdt_supernode_atdepth_offset(fdt, nodeoffset, 0, &nodedepth);



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