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| author | Jakub Jelinek <jakub@redhat.com> | 2022-03-24 12:23:51 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2022-03-24 12:23:51 +0100 |
| commit | 8698ff67cdff4364c8adad2921ed532359a155ec (patch) | |
| tree | 91d590dffc06408b709d71a8aceeeca7ebee3612 /gcc | |
| parent | d937c6e44ba64694c0fc88f40f42390149d1d624 (diff) | |
| download | gcc-8698ff67cdff4364c8adad2921ed532359a155ec.zip gcc-8698ff67cdff4364c8adad2921ed532359a155ec.tar.gz gcc-8698ff67cdff4364c8adad2921ed532359a155ec.tar.bz2 | |
fold-const: Handle C++ dependent COMPONENT_REFs in operand_equal_p [PR105035]
As mentioned in the PR, operand_equal_p already contains some hacks so that
it can be called already on pre-instantiation C++ trees from templates,
but the recent change to compare DECL_FIELD_OFFSET in the COMPONENT_REF
case broke this. Many such COMPONENT_REFs are already punted on earlier
because they have NULL TREE_TYPE, but in this case the code knows what
type they have but still uses an IDENTIFIER_NODE as second operand
of COMPONENT_REF (I think SCOPE_REF is something that could be used too).
The following patch looks at those DECL_FIELD_*OFFSET fields only if
both field[01] args are FIELD_DECLs and otherwise keeps it to the
earlier OP_SAME (1) check that guards this whole block.
2022-03-24 Jakub Jelinek <jakub@redhat.com>
PR c++/105035
* fold-const.cc (operand_equal_p) <case COMPONENT_REF>: If either
field0 or field1 is not a FIELD_DECL, return false.
* g++.dg/warn/Wduplicated-cond2.C: New test.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/fold-const.cc | 7 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/warn/Wduplicated-cond2.C | 29 |
2 files changed, 34 insertions, 2 deletions
diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc index 39a5a52..b647e53 100644 --- a/gcc/fold-const.cc +++ b/gcc/fold-const.cc @@ -3357,8 +3357,11 @@ operand_compare::operand_equal_p (const_tree arg0, const_tree arg1, tree field0 = TREE_OPERAND (arg0, 1); tree field1 = TREE_OPERAND (arg1, 1); - if (!operand_equal_p (DECL_FIELD_OFFSET (field0), - DECL_FIELD_OFFSET (field1), flags) + /* Non-FIELD_DECL operands can appear in C++ templates. */ + if (TREE_CODE (field0) != FIELD_DECL + || TREE_CODE (field1) != FIELD_DECL + || !operand_equal_p (DECL_FIELD_OFFSET (field0), + DECL_FIELD_OFFSET (field1), flags) || !operand_equal_p (DECL_FIELD_BIT_OFFSET (field0), DECL_FIELD_BIT_OFFSET (field1), flags)) diff --git a/gcc/testsuite/g++.dg/warn/Wduplicated-cond2.C b/gcc/testsuite/g++.dg/warn/Wduplicated-cond2.C new file mode 100644 index 0000000..c977389 --- /dev/null +++ b/gcc/testsuite/g++.dg/warn/Wduplicated-cond2.C @@ -0,0 +1,29 @@ +// PR c++/105035 +// { dg-do compile } +// { dg-options "-Wduplicated-cond" } + +class A { + struct B { int c; int f; } e; + template <typename> void foo (); + void bar (); +}; + +template <typename> void +A::foo () +{ + int g; + if (&g == &e.c) + ; + else if (&g == &e.f) + ; +} + +void +A::bar () +{ + int g; + if (&g == &e.c) // { dg-message "previously used here" } + ; + else if (&g == &e.c) // { dg-warning "duplicated 'if' condition" } + ; +} |