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| author | Jason Merrill <jason@redhat.com> | 2011-03-17 18:00:47 -0400 |
|---|---|---|
| committer | Jason Merrill <jason@gcc.gnu.org> | 2011-03-17 18:00:47 -0400 |
| commit | c598e5fa54f472696d5d50e2ba4991a3cec62dd1 (patch) | |
| tree | 01325d328412e2fe507949df5ebe3ca0566672e2 | |
| parent | 8b29c87a61bf1ea9aa4691dd3c07ef79119d790a (diff) | |
| download | gcc-c598e5fa54f472696d5d50e2ba4991a3cec62dd1.zip gcc-c598e5fa54f472696d5d50e2ba4991a3cec62dd1.tar.gz gcc-c598e5fa54f472696d5d50e2ba4991a3cec62dd1.tar.bz2 | |
re PR c++/47504 ([C++0x] some constexpr calculations erroneously overflow when using negative numbers)
PR c++/47504
* semantics.c (cxx_eval_constant_expression) [NOP_EXPR]: Don't let
the conversion set TREE_OVERFLOW.
From-SVN: r171116
| -rw-r--r-- | gcc/cp/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/cp/semantics.c | 5 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp0x/constexpr-data2.C | 1 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp0x/constexpr-overflow2.C | 8 |
5 files changed, 22 insertions, 1 deletions
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index f710f7a..51535f5 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,5 +1,9 @@ 2011-03-17 Jason Merrill <jason@redhat.com> + PR c++/47504 + * semantics.c (cxx_eval_constant_expression) [NOP_EXPR]: Don't let + the conversion set TREE_OVERFLOW. + Core 1212 * semantics.c (finish_decltype_type): Return T&& for xvalue. * typeck.c (unlowered_expr_type): Preserve cv-quals. diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c index cafca56..b6d1008 100644 --- a/gcc/cp/semantics.c +++ b/gcc/cp/semantics.c @@ -6991,6 +6991,11 @@ cxx_eval_constant_expression (const constexpr_call *call, tree t, conversion. */ return fold (t); r = fold_build1 (TREE_CODE (t), to, op); + /* Conversion of an out-of-range value has implementation-defined + behavior; the language considers it different from arithmetic + overflow, which is undefined. */ + if (TREE_OVERFLOW_P (r) && !TREE_OVERFLOW_P (op)) + TREE_OVERFLOW (r) = false; } break; diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index e0b94d4..c72c0e4 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2011-03-17 Jason Merrill <jason@redhat.com> + + * g++.dg/cpp0x/constexpr-overflow2.C: New. + * g++.dg/cpp0x/constexpr-data2.C: Remove FIXME. + 2011-03-17 Eric Botcazou <ebotcazou@adacore.com> * gnat.dg/specs/elab2.ads: New test. diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-data2.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-data2.C index 598cae6..2d614ec 100644 --- a/gcc/testsuite/g++.dg/cpp0x/constexpr-data2.C +++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-data2.C @@ -44,5 +44,4 @@ extern template struct A3<int, 510>; // Use. A3<int, 1111> a31; -// FIXME should this be an error? A3<char, 9999> a32; // { dg-warning "overflow" } diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-overflow2.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-overflow2.C new file mode 100644 index 0000000..5d5749c --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-overflow2.C @@ -0,0 +1,8 @@ +// PR c++/47504 +// { dg-options -std=c++0x } + +char constexpr sub(char arg) +{ return char(arg - char(1)); } + +int main() +{ static char constexpr m = sub(-1); } |