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| author | Marek Polacek <polacek@redhat.com> | 2020-02-19 16:36:38 -0500 |
|---|---|---|
| committer | Marek Polacek <polacek@redhat.com> | 2020-02-19 19:14:29 -0500 |
| commit | 8f9dd1b0bdd935592ba151e9d843fddf6193afbc (patch) | |
| tree | e19b0e3022901799a7fae3326655494fc1ad49a6 /gcc/cp/constexpr.c | |
| parent | ccf86d54cb02ed24bc4568bd9fffdcdbf0bf68a8 (diff) | |
| download | gcc-8f9dd1b0bdd935592ba151e9d843fddf6193afbc.zip gcc-8f9dd1b0bdd935592ba151e9d843fddf6193afbc.tar.gz gcc-8f9dd1b0bdd935592ba151e9d843fddf6193afbc.tar.bz2 | |
c++: Fix wrong-code with non-constexpr constructor [PR93169]
In order to detect modifying constant objects in constexpr evaluation,
which is UB, in r10-2655 I added code that sets TREE_READONLY on
CONSTRUCTORs of const-qualified objects after they have been fully
constructed. But I never made sure that what we're setting the flag
on actually is a CONSTRUCTOR. Consequently, as this test case shows,
we could set TREE_READONLY on a VAR_DECL that in fact wasn't constant,
causing problems later. Fixed by setting the flag on CONSTRUCTORs
only, and only when the evaluation produced something constant.
2020-02-19 Marek Polacek <polacek@redhat.com>
PR c++/93169 - wrong-code with a non-constexpr constructor.
* constexpr.c (cxx_eval_call_expression): Only set TREE_READONLY
on constant CONSTRUCTORs.
* g++.dg/cpp0x/constexpr-93169.C: New test.
Diffstat (limited to 'gcc/cp/constexpr.c')
| -rw-r--r-- | gcc/cp/constexpr.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c index bf7a264..128f760 100644 --- a/gcc/cp/constexpr.c +++ b/gcc/cp/constexpr.c @@ -2474,7 +2474,8 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, /*lval*/false, non_constant_p, overflow_p); - TREE_READONLY (e) = true; + if (TREE_CODE (e) == CONSTRUCTOR && !*non_constant_p) + TREE_READONLY (e) = true; } /* Forget the saved values of the callee's SAVE_EXPRs and |