On Fri, Sep 7, 2012 at 11:01 PM, Markus Trippelsdorf
<mar...@trippelsdorf.de> wrote:
> Here the problem is that get_base_address() can return NULL_TREE and
> this later leads to a segfault. Fix by checking that the return value is
> valid.
> gcc-4.6 and 4.7 are also affected.
>
> Please commit if this looks OK.
> Thanks.
Hmm, we call the function on
VIEW_CONVERT_EXPR<unsigned char[2]>(0)[0]
which should have been folded to a constant. And get_base_address
should just return the constant tree instead of returning NULL (it does
return a plethora of base object kinds already). Your patch looks ok for
the branches where I'll install it and come up with sth else for trunk.
Thanks,
Richard.
> Tested on x86_64-pc-linux-gnu
>
> 2012-09-07 Markus Trippelsdorf <mar...@trippelsdorf.de>
>
> PR middle-end/54515
> * tree-sra.c (disqualify_base_of_expr): Check for possible
> NULL_TREE returned by get_base_address()
>
> * g++.dg/tree-ssa/pr54515.C: new testcase
>
> diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr54515.C
> b/gcc/testsuite/g++.dg/tree-ssa/pr54515.C
> new file mode 100644
> index 0000000..11ed468
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/tree-ssa/pr54515.C
> @@ -0,0 +1,19 @@
> +// { dg-do compile }
> +// { dg-options "-O2" }
> +
> +template < typename T > T h2le (T)
> +{
> + T a;
> + unsigned short &b = a;
> + short c = 0;
> + unsigned char (&d)[2] = reinterpret_cast < unsigned char (&)[2] > (c);
> + unsigned char (&e)[2] = reinterpret_cast < unsigned char (&)[2] > (b);
> + e[0] = d[0];
> + return a;
> +}
> +
> +void
> +bar ()
> +{
> + h2le ((unsigned short) 0);
> +}
> diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
> index aafaa15..2bb92e9 100644
> --- a/gcc/tree-sra.c
> +++ b/gcc/tree-sra.c
> @@ -984,7 +984,8 @@ static void
> disqualify_base_of_expr (tree t, const char *reason)
> {
> t = get_base_address (t);
> - if (sra_mode == SRA_MODE_EARLY_IPA
> + if (t
> + && sra_mode == SRA_MODE_EARLY_IPA
> && TREE_CODE (t) == MEM_REF)
> t = get_ssa_base_param (TREE_OPERAND (t, 0));
>
> --
> Markus
