[PATCH] Avoid creating (mem (debug_implict_ptr)) (PR debug/47283)
Richard Guenther
richard.guenther@gmail.com
Thu Jan 20 16:32:00 GMT 2011
On Thu, Jan 20, 2011 at 5:23 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> MEMs for something that is not addressable just confuse the aliasing
> code (expectedly) and furthermore result in unnecessarily large
> location description (DW_OP_GNU_implicit_pointer followed by
> DW_OP_deref*). This patch in that case just uses the
> COMPONENT_REF/ARRAY_REF etc. handling code, which will expand it as a SUBREG
> or similar.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok.
Thanks,
Richard.
> 2011-01-20 Jakub Jelinek <jakub@redhat.com>
>
> PR debug/47283
> * cfgexpand.c (expand_debug_expr): Instead of generating
> (mem (debug_implicit_ptr)) for MEM_REFs use COMPONENT_REF
> etc. handling.
>
> * g++.dg/debug/pr47283.C: New test.
>
> --- gcc/cfgexpand.c.jj 2011-01-03 09:54:28.000000000 +0100
> +++ gcc/cfgexpand.c 2011-01-20 09:59:09.000000000 +0100
> @@ -2567,6 +2567,13 @@ expand_debug_expr (tree exp)
>
> if (TREE_CODE (exp) == MEM_REF)
> {
> + if (GET_CODE (op0) == DEBUG_IMPLICIT_PTR
> + || (GET_CODE (op0) == PLUS
> + && GET_CODE (XEXP (op0, 0)) == DEBUG_IMPLICIT_PTR))
> + /* (mem (debug_implicit_ptr)) might confuse aliasing.
> + Instead just use get_inner_reference. */
> + goto component_ref;
> +
> op1 = expand_debug_expr (TREE_OPERAND (exp, 1));
> if (!op1 || !CONST_INT_P (op1))
> return NULL;
> @@ -2605,6 +2612,7 @@ expand_debug_expr (tree exp)
>
> return op0;
>
> + component_ref:
> case ARRAY_REF:
> case ARRAY_RANGE_REF:
> case COMPONENT_REF:
> --- gcc/testsuite/g++.dg/debug/pr47283.C.jj 2011-01-20 10:11:09.000000000 +0100
> +++ gcc/testsuite/g++.dg/debug/pr47283.C 2011-01-20 10:13:16.000000000 +0100
> @@ -0,0 +1,58 @@
> +// PR debug/47283
> +// { dg-do compile }
> +
> +template <typename T> inline const T &
> +f1 (const T &a, const T &b)
> +{
> + if (a < b)
> + return b;
> + return a;
> +};
> +
> +struct A
> +{
> + A (int w, int h) { a1 = w; }
> + A f2 (const A &) const;
> + int a1, a2;
> +};
> +
> +inline A
> +A::f2 (const A &x) const
> +{
> + return A (f1 (a1, x.a1), f1 (a2, x.a2));
> +};
> +
> +struct B
> +{
> + A f3 () const;
> + void f4 (const A &) { b2 = 5 + b1; }
> + int b1, b2;
> +};
> +
> +struct C
> +{
> +};
> +
> +struct D
> +{
> + virtual C f5 (const C &) const;
> +};
> +
> +struct E
> +{
> + C f6 () const;
> + int f7 () const;
> + virtual B f8 (const C &) const;
> + A f9 () const;
> + virtual void f10 ();
> + struct F { D *h; } *d;
> +};
> +
> +void
> +E::f10 ()
> +{
> + const C c = d->h->f5 (f6 ());
> + B b = f8 (c);
> + b.f4 (b.f3 ().f2 (f9 ()));
> + f7 ();
> +}
>
> Jakub
>
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