On 28/10/15 12:10, Richard Biener wrote:
On Wed, 28 Oct 2015, Tom de Vries wrote:
Richard,
when compiling this testcase:
...
static int __attribute__((noinline, noclone))
foo (int *a, int *b)
{
*b = 1;
*a = 2;
return *b;
}
int __attribute__((noinline, noclone))
bar (int *a, int *b)
{
return foo (a, b);
}
...
with -O2 -fipa-pta we find in the pta dumpfile:
...
Generating constraints for bar (bar)
bar.arg0 = &NONLOCAL
bar.arg1 = &NONLOCAL
bar.arg1 = &NONLOCAL
...
The reason for the duplicate last two constraints is that with fipa-pta, in
create_function_info_for we link the function arguments in a next chain.
And in intra_create_variable_infos there are two iteration mechanism used:
- the loop over the function arguments
- the loop over the vi_next (p) for each function argument p
So when processing argument a, we generate constraints for both a and it's
next b.
And when processing argument b, we generate constraints for b again.
Is this a known issue? Should we fix this?
Didn't see that yet. Yes, we should fix it.
Index: gcc/tree-ssa-structalias.c
===================================================================
--- gcc/tree-ssa-structalias.c (revision 229481)
+++ gcc/tree-ssa-structalias.c (working copy)
@@ -5913,6 +6009,8 @@ intra_create_variable_infos (struct func
make_constraint_from_global_restrict (p, "PARM_RESTRICT");
else if (p->may_have_pointers)
make_constraint_from (p, nonlocal_id);
+ if (p->is_full_var)
+ break;
}
}
}
does for me. Pre-approved if it passes testing.
Tested and committed. Posting with ChangeLog entry.
Thanks,
- Tom
Generate constraints only once in intra_create_variable_infos
2015-10-28 Tom de Vries <t...@codesourcery.com>
* tree-ssa-structalias.c (intra_create_variable_infos): Don't iterate
into vi_next of a full_var.
---
gcc/tree-ssa-structalias.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index 07ec4a5..06415a2 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -5924,6 +5924,8 @@ intra_create_variable_infos (struct function *fn)
make_constraint_from_global_restrict (p, "PARM_RESTRICT", true);
else if (p->may_have_pointers)
make_constraint_from (p, nonlocal_id);
+ if (p->is_full_var)
+ break;
}
}
}
--
1.9.1
