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| author | Jakub Jelinek <jakub@redhat.com> | 2020-08-10 17:53:46 +0200 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2020-08-10 17:53:46 +0200 |
| commit | 5c64df80df274c753bfc8415bd902e1180e76f6a (patch) | |
| tree | dca9a6c4f6f0d7f8ab211c5b3e23a492c3dec49a | |
| parent | 41fd9d26108fc98bbffce3d99d218a6a09fa80c6 (diff) | |
| download | gcc-5c64df80df274c753bfc8415bd902e1180e76f6a.zip gcc-5c64df80df274c753bfc8415bd902e1180e76f6a.tar.gz gcc-5c64df80df274c753bfc8415bd902e1180e76f6a.tar.bz2 | |
c++: Fix constexpr evaluation of SPACESHIP_EXPR [PR96497]
The following valid testcase is rejected, because cxx_eval_binary_expression
is called on the SPACESHIP_EXPR with lval = true, as the address of the
spaceship needs to be passed to a method call.
After recursing on the operands and calling genericize_spaceship which turns
it into a TARGET_EXPR with initialization, we call cxx_eval_constant_expression
on it which succeeds, but then we fall through into code that will
VERIFY_CONSTANT (r) which FAILs because it is an address of a variable. Rather
than avoiding that for lval = true and SPACESHIP_EXPR, the patch just tail
calls cxx_eval_constant_expression - I believe that call should perform all
the needed verifications.
2020-08-10 Jakub Jelinek <jakub@redhat.com>
PR c++/96497
* constexpr.c (cxx_eval_binary_expression): For SPACESHIP_EXPR, tail
call cxx_eval_constant_expression after genericize_spaceship to avoid
undesirable further VERIFY_CONSTANT.
* g++.dg/cpp2a/spaceship-constexpr3.C: New test.
| -rw-r--r-- | gcc/cp/constexpr.c | 4 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp2a/spaceship-constexpr3.C | 7 |
2 files changed, 9 insertions, 2 deletions
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c index ab747a5..8ee0f2a 100644 --- a/gcc/cp/constexpr.c +++ b/gcc/cp/constexpr.c @@ -3085,8 +3085,8 @@ cxx_eval_binary_expression (const constexpr_ctx *ctx, tree t, else if (code == SPACESHIP_EXPR) { r = genericize_spaceship (type, lhs, rhs); - r = cxx_eval_constant_expression (ctx, r, lval, non_constant_p, - overflow_p); + return cxx_eval_constant_expression (ctx, r, lval, non_constant_p, + overflow_p); } if (r == NULL_TREE) diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-constexpr3.C b/gcc/testsuite/g++.dg/cpp2a/spaceship-constexpr3.C new file mode 100644 index 0000000..95f03e6 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-constexpr3.C @@ -0,0 +1,7 @@ +// PR c++/96497 +// { dg-do compile { target c++20 } } + +#include <compare> + +static_assert(std::partial_ordering(std::strong_ordering::less) < 0); +static_assert(std::partial_ordering(1 <=> 2) < 0); |