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| author | Jakub Jelinek <jakub@redhat.com> | 2021-03-19 18:36:56 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2021-03-19 18:36:56 +0100 |
| commit | 82bb66730bc42b8694fdebef607ea6e49e8496bf (patch) | |
| tree | 7c7282833d2a07704bea93c4f10887d073d4f498 /gcc/cp/constexpr.c | |
| parent | 02f305440f29c68b7368c9af9ae689cce6d26d6d (diff) | |
| download | gcc-82bb66730bc42b8694fdebef607ea6e49e8496bf.zip gcc-82bb66730bc42b8694fdebef607ea6e49e8496bf.tar.gz gcc-82bb66730bc42b8694fdebef607ea6e49e8496bf.tar.bz2 | |
c++: Only reject reinterpret casts from pointers to integers for manifestly_const_eval evaluation [PR99456]
My PR82304/PR95307 fix moved reinterpret cast from pointer to integer
diagnostics from cxx_eval_outermost_constant_expr where it caught
invalid code only at the outermost level down into
cxx_eval_constant_expression.
Unfortunately, it regressed following testcase, we emit worse code
including dynamic initialization of some vars.
While the initializers are not constant expressions due to the
reinterpret_cast in there, there is no reason not to fold them as an
optimization.
I've tried to make this dependent on !ctx->quiet, but that regressed
two further tests, and on ctx->strict, which regressed other tests,
so this patch bases that on manifestly_const_eval.
The new testcase is now optimized as much as it used to be in GCC 10
and the only regression it causes is an extra -Wnarrowing warning
on vla22.C test on invalid code (which the patch adjusts).
2021-03-19 Jakub Jelinek <jakub@redhat.com>
PR c++/99456
* constexpr.c (cxx_eval_constant_expression): For CONVERT_EXPR from
INDIRECT_TYPE_P to ARITHMETIC_TYPE_P, when !ctx->manifestly_const_eval
don't diagnose it, set *non_constant_p nor return t.
* g++.dg/opt/pr99456.C: New test.
* g++.dg/ext/vla22.C: Expect a -Wnarrowing warning for c++11 and
later.
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 c946744..42d00ec 100644 --- a/gcc/cp/constexpr.c +++ b/gcc/cp/constexpr.c @@ -6656,7 +6656,8 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, if (TREE_CODE (t) == CONVERT_EXPR && ARITHMETIC_TYPE_P (type) - && INDIRECT_TYPE_P (TREE_TYPE (op))) + && INDIRECT_TYPE_P (TREE_TYPE (op)) + && ctx->manifestly_const_eval) { if (!ctx->quiet) error_at (loc, |