Re: [RFC][IPA-VRP] ADDR_EXPR and nonnull

[kugan]

Hi Richard,

On 19/10/16 19:23, Richard Biener wrote:
On Wed, 19 Oct 2016, kugan wrote:

Hi,

While computing jump function value range for pointer, I am wondering if we
can assume that any tree with ADDR_EXPR will be nonnull.

That is, in cases like:

int arr[10];
foo (&arr[1]);

OR

struct st
{
  int a;
  int b;
};
struct st s2;
foo (&s2.a);

Attached patch tries to do this. I am not sure if this can be wrong. Any
thoughts?

It can be wrong for weak symbols for example.
Would excluding weak symbols (I believe I can check DECL_WEAK for this) 
good enough. Or looking for acceptable subset would work?

Thanks,
Kugan


Richard.

Attached patch bootstraps and regression testing didn't introduce any new
regressions.

Thanks,
Kugan


gcc/ChangeLog:

2016-10-19  Kugan Vivekanandarajah  <kug...@linaro.org>

        * ipa-prop.c (ipa_compute_jump_functions_for_edge): Set
        value range to nonull for ADDR_EXPR.

gcc/testsuite/ChangeLog:

2016-10-19  Kugan Vivekanandarajah  <kug...@linaro.org>

        * gcc.dg/ipa/vrp5.c: New test.
        * gcc.dg/ipa/vrp6.c: New test.