On Fri, 12 Apr 2019, Richard Biener wrote:
> On Fri, 12 Apr 2019, Michael Matz wrote:
>
> > Hi,
> >
> > On Fri, 12 Apr 2019, Richard Biener wrote:
> >
> > > > You miss PARM_DECLs and RESULT_DECLs, i.e. it's probably better to
> > > > factor
> > > > out tree.c:auto_var_in_fn_p and place the new auto_var_p in tree.c as
> > > > well.
> > >
> > > Hmm, I left the above unchanged from a different variant of the patch
> > > where for some reason I do not remember I explicitely decided
> > > parameters and results are not affected...
> >
> > Even if that were the case the function is sufficiently general (also its
> > name) that it should be generic infrastructure, not hidden away in
> > structalias.
>
> It was not fully equivalent, but yes. So - like the following?
> I think checking DECL_CONTEXT isn't necessary given the
> !DECL_EXTERNAL/STATIC checks.
>
> Bootstrap / regtest running on x86_64-unknown-linux-gnu.
Aww, hits
/space/rguenther/src/svn/trunk/libgomp/testsuite/libgomp.oacc-c/../libgomp.oacc-c-c++-common/zero_length_subarrays.c:33:1:
internal compiler error: in fold_builtin_alloca_with_align, at
tree-ssa-ccp.c:2186^M
0x6d7e45 fold_builtin_alloca_with_align^M
have to look/think about this.
Richard.
> Richard.
>
> 2019-04-12 Richard Biener <rguent...@suse.de>
>
> PR ipa/88936
> * tree.h (auto_var_p): Declare.
> * tree.c (auto_var_p): New function, split out from ...
> (auto_var_in_fn_p): ... here.
> * tree-ssa-structalias.c (struct variable_info): Add shadow_var_uid
> member.
> (new_var_info): Initialize it.
> (set_uids_in_ptset): Also set the shadow variable uid if required.
> (ipa_pta_execute): Postprocess points-to solutions assigning
> shadow variable uids for locals that may reach their containing
> function recursively.
>
> * gcc.dg/torture/pr88936-1.c: New testcase.
> * gcc.dg/torture/pr88936-2.c: Likewise.
> * gcc.dg/torture/pr88936-3.c: Likewise.
>
> Index: gcc/tree.c
> ===================================================================
> --- gcc/tree.c (revision 270306)
> +++ gcc/tree.c (working copy)
> @@ -9268,17 +9268,25 @@ get_type_static_bounds (const_tree type,
> }
> }
>
> +/* Return true if VAR is an automatic variable. */
> +
> +bool
> +auto_var_p (const_tree var)
> +{
> + return ((((VAR_P (var) && ! DECL_EXTERNAL (var))
> + || TREE_CODE (var) == PARM_DECL)
> + && ! TREE_STATIC (var))
> + || TREE_CODE (var) == RESULT_DECL);
> +}
> +
> /* Return true if VAR is an automatic variable defined in function FN. */
>
> bool
> auto_var_in_fn_p (const_tree var, const_tree fn)
> {
> return (DECL_P (var) && DECL_CONTEXT (var) == fn
> - && ((((VAR_P (var) && ! DECL_EXTERNAL (var))
> - || TREE_CODE (var) == PARM_DECL)
> - && ! TREE_STATIC (var))
> - || TREE_CODE (var) == LABEL_DECL
> - || TREE_CODE (var) == RESULT_DECL));
> + && (auto_var_p (var)
> + || TREE_CODE (var) == LABEL_DECL));
> }
>
> /* Subprogram of following function. Called by walk_tree.
> Index: gcc/tree.h
> ===================================================================
> --- gcc/tree.h (revision 270306)
> +++ gcc/tree.h (working copy)
> @@ -4893,6 +4893,7 @@ extern bool stdarg_p (const_tree);
> extern bool prototype_p (const_tree);
> extern bool is_typedef_decl (const_tree x);
> extern bool typedef_variant_p (const_tree);
> +extern bool auto_var_p (const_tree);
> extern bool auto_var_in_fn_p (const_tree, const_tree);
> extern tree build_low_bits_mask (tree, unsigned);
> extern bool tree_nop_conversion_p (const_tree, const_tree);
> Index: gcc/tree-ssa-structalias.c
> ===================================================================
> --- gcc/tree-ssa-structalias.c (revision 270306)
> +++ gcc/tree-ssa-structalias.c (working copy)
> @@ -299,6 +299,11 @@ struct variable_info
> /* Full size of the base variable, in bits. */
> unsigned HOST_WIDE_INT fullsize;
>
> + /* In IPA mode the shadow UID in case the variable needs to be duplicated
> in
> + the final points-to solution because it reaches its containing
> + function recursively. Zero if none is needed. */
> + unsigned int shadow_var_uid;
> +
> /* Name of this variable */
> const char *name;
>
> @@ -397,6 +402,7 @@ new_var_info (tree t, const char *name,
> ret->solution = BITMAP_ALLOC (&pta_obstack);
> ret->oldsolution = NULL;
> ret->next = 0;
> + ret->shadow_var_uid = 0;
> ret->head = ret->id;
>
> stats.total_vars++;
> @@ -6452,6 +6458,16 @@ set_uids_in_ptset (bitmap into, bitmap f
> && (TREE_STATIC (vi->decl) || DECL_EXTERNAL (vi->decl))
> && ! decl_binds_to_current_def_p (vi->decl))
> pt->vars_contains_interposable = true;
> +
> + /* If this is a local variable we can have overlapping lifetime
> + of different function invocations through recursion duplicate
> + it with its shadow variable. */
> + if (in_ipa_mode
> + && vi->shadow_var_uid != 0)
> + {
> + bitmap_set_bit (into, vi->shadow_var_uid);
> + pt->vars_contains_nonlocal = true;
> + }
> }
>
> else if (TREE_CODE (vi->decl) == FUNCTION_DECL
> @@ -8076,6 +8095,62 @@ ipa_pta_execute (void)
> /* From the constraints compute the points-to sets. */
> solve_constraints ();
>
> + /* Now post-process solutions to handle locals from different
> + runtime instantiations coming in through recursive invocations. */
> + unsigned shadow_var_cnt = 0;
> + for (unsigned i = 1; i < varmap.length (); ++i)
> + {
> + varinfo_t fi = get_varinfo (i);
> + if (fi->is_fn_info
> + && fi->decl)
> + /* Automatic variables pointed to by their containing functions
> + parameters need this treatment. */
> + for (varinfo_t ai = first_vi_for_offset (fi, fi_parm_base);
> + ai; ai = vi_next (ai))
> + {
> + varinfo_t vi = get_varinfo (find (ai->id));
> + bitmap_iterator bi;
> + unsigned j;
> + EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, j, bi)
> + {
> + varinfo_t pt = get_varinfo (j);
> + if (pt->shadow_var_uid == 0
> + && pt->decl
> + && auto_var_in_fn_p (pt->decl, fi->decl))
> + {
> + pt->shadow_var_uid = allocate_decl_uid ();
> + shadow_var_cnt++;
> + }
> + }
> + }
> + /* As well as global variables which are another way of passing
> + arguments to recursive invocations. */
> + else if (fi->is_global_var)
> + {
> + for (varinfo_t ai = fi; ai; ai = vi_next (ai))
> + {
> + varinfo_t vi = get_varinfo (find (ai->id));
> + bitmap_iterator bi;
> + unsigned j;
> + EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, j, bi)
> + {
> + varinfo_t pt = get_varinfo (j);
> + if (pt->shadow_var_uid == 0
> + && pt->decl
> + && auto_var_p (pt->decl))
> + {
> + pt->shadow_var_uid = allocate_decl_uid ();
> + shadow_var_cnt++;
> + }
> + }
> + }
> + }
> + }
> + if (shadow_var_cnt && dump_file && (dump_flags & TDF_DETAILS))
> + fprintf (dump_file, "Allocated %u shadow variables for locals "
> + "maybe leaking into recursive invocations of their containing "
> + "functions\n", shadow_var_cnt);
> +
> /* Compute the global points-to sets for ESCAPED.
> ??? Note that the computed escape set is not correct
> for the whole unit as we fail to consider graph edges to
> Index: gcc/testsuite/gcc.dg/torture/pr88936-1.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/torture/pr88936-1.c (nonexistent)
> +++ gcc/testsuite/gcc.dg/torture/pr88936-1.c (working copy)
> @@ -0,0 +1,27 @@
> +/* { dg-do run } */
> +/* { dg-additional-options "-fipa-pta" } */
> +
> +static long bug (long depth, long * v)
> +{
> + if (depth == 0)
> + {
> + *v = 0;
> + return 1;
> + }
> +
> + long r = 1;
> + long val = bug(depth - 1, &r);
> + return 2 * r + val;
> +}
> +
> +static long ff (long depth)
> +{
> + return bug(depth, (long*)0);
> +}
> +
> +int main()
> +{
> + if (ff(1) != 1)
> + __builtin_abort ();
> + return 0;
> +}
> Index: gcc/testsuite/gcc.dg/torture/pr88936-2.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/torture/pr88936-2.c (nonexistent)
> +++ gcc/testsuite/gcc.dg/torture/pr88936-2.c (working copy)
> @@ -0,0 +1,22 @@
> +/* { dg-do run } */
> +/* { dg-additional-options "-fipa-pta" } */
> +
> +static int *p;
> +void bar(int cnt)
> +{
> + int i = 0;
> + if (cnt == 0)
> + {
> + p = &i;
> + bar (1);
> + if (i != 1)
> + __builtin_abort ();
> + }
> + else if (cnt == 1)
> + *p = 1;
> +}
> +int main()
> +{
> + bar (0);
> + return 0;
> +}
> Index: gcc/testsuite/gcc.dg/torture/pr88936-3.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/torture/pr88936-3.c (nonexistent)
> +++ gcc/testsuite/gcc.dg/torture/pr88936-3.c (working copy)
> @@ -0,0 +1,21 @@
> +/* { dg-do run } */
> +/* { dg-additional-options "-fipa-pta" } */
> +
> +static int *p;
> +void bar(int cnt)
> +{
> + if (cnt == 0)
> + {
> + p = &cnt;
> + bar (1);
> + if (cnt != 1)
> + __builtin_abort ();
> + }
> + else if (cnt == 1)
> + *p = 1;
> +}
> +int main()
> +{
> + bar (0);
> + return 0;
> +}
>
--
Richard Biener <rguent...@suse.de>
SUSE Linux GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany;
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah; HRB 21284 (AG Nürnberg)
