Hi,
As Jakub reminded me, I introduced OEP_MATCH_SIDE_EFFECTS for cases like
ICF or tail merging where we merge accesses from different code paths.
By default operand_equal_p is designed for accesses from one code path
where we do not want to merge two side effects.
Since compare_ao_refs is currently used only in ICF, we should use it.
If in future it is used in other contextes, perhaps we need a parameter
controlling it, but for now I think adding OEP_MATCH_SIDE_EFFECTS is
good way to go.
This enables merging of volatile accesses in Firefox (we check that the
other access is also volatile).
With this on libxul build we get:
571 libxul.so.wpa.076i.icf: false returned: 'compare_ao_refs failed
(dependence clique difference)' in compare_operand at
../../gcc/ipa-icf-gimple.c:373
676 libxul.so.wpa.076i.icf: false returned: 'compare_ao_refs failed
(semantic difference)' in compare_operand at ../../gcc/ipa-icf-gimple.c:361
676 libxul.so.wpa.076i.icf: false returned: 'METHOD_TYPE and FUNCTION_TYPE
mismatch' in equals_wpa at ../../gcc/ipa-icf.c:674
707 libxul.so.wpa.076i.icf: false returned: 'operand_equal_p failed' in
compare_operand at ../../gcc/ipa-icf-gimple.c:381
Which is very low. I will still analyze the remaining 707
operand_equal_p failures. Some of them are deffects how we match
parameters:
_9 = Schedule (this_3(D), aManifestURI_4(D), aDocumentURI_5(D),
aLoadingPrincipal_6(D), 0B, aWindow_2(D), 0B, aUpdate_7(D));
_9 = Schedule (this_2(D), aManifestURI_3(D), aDocumentURI_4(D),
aLoadingPrincipal_5(D), 0B, 0B, aProfileDir_6(D), aUpdate_7(D));
Since we do not hash anyting ofr SSA_NAME see it as Schedule (0,0) in
bot cases. I am testing fix.
Bootstrapped/regtested x86_64-linux, OK?
Honza
* tree-ssa-alias.c (ao_compare::compare_ao_refs,
ao_compare::hash_ao_ref): Use OEP_MATCH_SIDE_EFFECTS.
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index 5ebbb087285..311ce66892b 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -3985,11 +3985,12 @@ ao_compare::compare_ao_refs (ao_ref *ref1, ao_ref *ref2,
return SEMANTICS;
/* Now we can compare the address of actual memory access. */
- if (!operand_equal_p (r1, r2, OEP_ADDRESS_OF))
+ if (!operand_equal_p (r1, r2, OEP_ADDRESS_OF | OEP_MATCH_SIDE_EFFECTS))
return SEMANTICS;
}
/* For constant accesses we get more matches by comparing offset only. */
- else if (!operand_equal_p (base1, base2, OEP_ADDRESS_OF))
+ else if (!operand_equal_p (base1, base2,
+ OEP_ADDRESS_OF | OEP_MATCH_SIDE_EFFECTS))
return SEMANTICS;
/* We can't simply use get_object_alignment_1 on the full
@@ -4197,11 +4198,11 @@ ao_compare::hash_ao_ref (ao_ref *ref, bool
lto_streaming_safe, bool tbaa,
r = TREE_OPERAND (r, 0);
}
hash_operand (TYPE_SIZE (TREE_TYPE (ref->ref)), hstate, 0);
- hash_operand (r, hstate, OEP_ADDRESS_OF);
+ hash_operand (r, hstate, OEP_ADDRESS_OF | OEP_MATCH_SIDE_EFFECTS);
}
else
{
- hash_operand (tbase, hstate, OEP_ADDRESS_OF);
+ hash_operand (tbase, hstate, OEP_ADDRESS_OF | OEP_MATCH_SIDE_EFFECTS);
hstate.add_poly_int (ref->offset);
hstate.add_poly_int (ref->size);
hstate.add_poly_int (ref->max_size);
