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| author | Patrick Palka <ppalka@redhat.com> | 2022-06-23 16:36:43 -0400 |
|---|---|---|
| committer | Patrick Palka <ppalka@redhat.com> | 2022-06-23 16:36:43 -0400 |
| commit | b00b95198e6720eb23a2618870d67800f6180fdd (patch) | |
| tree | 7a13650a79c41666833341dabc72dfacd7a90700 /gcc/cp/expr.cc | |
| parent | 01aff2ba18a654324957af446a3065db489c0f14 (diff) | |
| download | gcc-b00b95198e6720eb23a2618870d67800f6180fdd.zip gcc-b00b95198e6720eb23a2618870d67800f6180fdd.tar.gz gcc-b00b95198e6720eb23a2618870d67800f6180fdd.tar.bz2 | |
c++: constexpr folding in unevaluated context [PR105931]
Changing the type of N from int to unsigned in decltype82.C (from
r13-986-g0ecb6b906f215e) reveals another spot where we perform constexpr
evaluation in an unevaluated context for sake of warnings, this time
from the call to shorten_compare in cp_build_binary_op, which calls
fold_for_warn.
We could (and probably should) suppress the shorten_compare warnings
when in an unevaluated context, but there's probably other callers of
fold_for_warn that are similarly affected. So this patch takes the
approach of directly suppressing fold_for_warn when in an unevaluated
context.
PR c++/105931
gcc/cp/ChangeLog:
* expr.cc (fold_for_warn): Don't fold when in an unevaluated
context.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/decltype82a.C: New test.
Diffstat (limited to 'gcc/cp/expr.cc')
| -rw-r--r-- | gcc/cp/expr.cc | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/gcc/cp/expr.cc b/gcc/cp/expr.cc index 31fe098..56fc11f 100644 --- a/gcc/cp/expr.cc +++ b/gcc/cp/expr.cc @@ -397,6 +397,11 @@ fold_for_warn (tree x) { /* C++ implementation. */ + if (cp_unevaluated_operand) + /* In an unevaluated context we don't care about the reduced value + of an expression, so neither should any warnings. */ + return x; + /* Prevent warning-dependent constexpr evaluation from changing DECL_UID (which breaks -fcompare-debug) and from instantiating templates. */ |