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| author | Marek Polacek <polacek@redhat.com> | 2024-09-17 14:34:30 -0400 |
|---|---|---|
| committer | Marek Polacek <polacek@redhat.com> | 2024-09-17 17:04:20 -0400 |
| commit | d6d8445c85509b66a59aa6247ad7b2cfeab17725 (patch) | |
| tree | 23072283ba1e3363c7a5ac78e3cc6f7c498eb49c | |
| parent | 7ca486889b1b1c7e7bcbbca3b6caa103294ec07d (diff) | |
| download | gcc-d6d8445c85509b66a59aa6247ad7b2cfeab17725.zip gcc-d6d8445c85509b66a59aa6247ad7b2cfeab17725.tar.gz gcc-d6d8445c85509b66a59aa6247ad7b2cfeab17725.tar.bz2 | |
c++: fix constexpr cast from void* diag issue [PR116741]
The result of build_fold_indirect_ref can be a COMPONENT_REF in
which case using DECL_SOURCE_LOCATION will crash. Look at its op1
instead.
PR c++/116741
gcc/cp/ChangeLog:
* constexpr.cc (cxx_eval_constant_expression) <case CONVERT_EXPR>: If
the result of build_fold_indirect_ref is a COMPONENT_REF, use its op1.
Check DECL_P before calling inform.
gcc/testsuite/ChangeLog:
* g++.dg/cpp26/constexpr-voidptr4.C: New test.
Reviewed-by: Jason Merrill <jason@redhat.com>
| -rw-r--r-- | gcc/cp/constexpr.cc | 7 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp26/constexpr-voidptr4.C | 29 |
2 files changed, 34 insertions, 2 deletions
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index c3668b0..f6fd059 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -8201,8 +8201,11 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, TREE_TYPE (op), TREE_TYPE (TREE_TYPE (sop)), TREE_TYPE (type)); tree obj = build_fold_indirect_ref (sop); - inform (DECL_SOURCE_LOCATION (obj), - "pointed-to object declared here"); + if (TREE_CODE (obj) == COMPONENT_REF) + obj = TREE_OPERAND (obj, 1); + if (DECL_P (obj)) + inform (DECL_SOURCE_LOCATION (obj), + "pointed-to object declared here"); } *non_constant_p = true; return t; diff --git a/gcc/testsuite/g++.dg/cpp26/constexpr-voidptr4.C b/gcc/testsuite/g++.dg/cpp26/constexpr-voidptr4.C new file mode 100644 index 0000000..53563c9 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp26/constexpr-voidptr4.C @@ -0,0 +1,29 @@ +// PR c++/116741 +// { dg-do compile { target c++26 } } + +struct S { + int foo; // { dg-message "pointed-to object" } +}; + +struct S2 { + int foo; // { dg-message "pointed-to object" } +}; + +struct X { + S2 s; +}; + +constexpr float f1() { + S s; + void* p = &s.foo; + return *static_cast<float*>(p); // { dg-error "not allowed in a constant expression" } +} + +constexpr float f2() { + X x; + void* p = &x.s.foo; + return *static_cast<float*>(p); // { dg-error "not allowed in a constant expression" } +} + +constexpr auto x1 = f1(); +constexpr auto x2 = f2(); |