| Message ID | 7447720.EvYhyI6sBW@fomalhaut |
|---|---|
| State | New |
| Headers | show |
| Series | Fix recent thinko in operand_equal_p | expand |
> Am 04.11.2022 um 10:29 schrieb Eric Botcazou via Gcc-patches <gcc-patches@gcc.gnu.org>: > > Hi, > > there is a thinko in the recent improvement by Jan: > > 2020-11-19 Jan Hubicka <jh@suse.cz> > > * fold-const.c (operand_compare::operand_equal_p): Fix thinko in > COMPONENT_REF handling and guard types_same_for_odr by > virtual_method_call_p. > (operand_compare::hash_operand): Likewise. > > where the code just looks at operand 2 of COMPONENT_REF, if it is present, to > compare addresses. That's wrong because operand 2 contains the number of > DECL_OFFSET_ALIGN-bit-sized words so, when DECL_OFFSET_ALIGN > 8, not all the > bytes are included and some of them are in DECL_FIELD_BIT_OFFSET instead, see > get_inner_reference for the model computation. > > In other words, you would need to compare operand 2 and DECL_OFFSET_ALIGN and > DECL_FIELD_BIT_OFFSET in this situation, but I'm not sure this is worth the > hassle in practice so the attached fix just removes this alternate handling. > Tested on x86-64/Linux, OK for mainline, 12 and 11 branches? Ok. Thanks, Richard > > 2022-11-04 Eric Botcazou <ebotcazou@adacore.com> > > * fold-const.cc (operand_compare::operand_equal_p) <COMPONENT_REF>: > Do not take into account operand 2. > (operand_compare::hash_operand) <COMPONENT_REF>: Likewise. > > > 2022-11-04 Eric Botcazou <ebotcazou@adacore.com> > > * gnat.dg/opt99.adb: New test. > * gnat.dg/opt99_pkg1.ads, gnat.dg/opt99_pkg1.adb: New helper. > * gnat.dg/opt99_pkg2.ads: Likewise. > > -- > Eric Botcazou > <p.diff> > <opt99.adb> > <opt99_pkg1.adb> > <opt99_pkg2.ads> > <opt99_pkg1.ads>
diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc index 9f7beae14e5..e7a9d5215a5 100644 --- a/gcc/fold-const.cc +++ b/gcc/fold-const.cc @@ -3351,9 +3351,6 @@ operand_compare::operand_equal_p (const_tree arg0, const_tree arg1, if (compare_address && (flags & OEP_ADDRESS_OF_SAME_FIELD) == 0) { - if (TREE_OPERAND (arg0, 2) - || TREE_OPERAND (arg1, 2)) - return OP_SAME_WITH_NULL (2); tree field0 = TREE_OPERAND (arg0, 1); tree field1 = TREE_OPERAND (arg1, 1); @@ -3864,17 +3861,10 @@ operand_compare::hash_operand (const_tree t, inchash::hash &hstate, if (sflags & OEP_ADDRESS_OF) { hash_operand (TREE_OPERAND (t, 0), hstate, flags); - if (TREE_OPERAND (t, 2)) - hash_operand (TREE_OPERAND (t, 2), hstate, - flags & ~OEP_ADDRESS_OF); - else - { - tree field = TREE_OPERAND (t, 1); - hash_operand (DECL_FIELD_OFFSET (field), - hstate, flags & ~OEP_ADDRESS_OF); - hash_operand (DECL_FIELD_BIT_OFFSET (field), - hstate, flags & ~OEP_ADDRESS_OF); - } + hash_operand (DECL_FIELD_OFFSET (TREE_OPERAND (t, 1)), + hstate, flags & ~OEP_ADDRESS_OF); + hash_operand (DECL_FIELD_BIT_OFFSET (TREE_OPERAND (t, 1)), + hstate, flags & ~OEP_ADDRESS_OF); return; } break;