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| author | Jakub Jelinek <jakub@redhat.com> | 2024-04-04 10:47:52 +0200 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2024-06-20 15:07:38 +0200 |
| commit | 5d6b1d8ffc4828874ecdb1cde1b794bc3b8d35af (patch) | |
| tree | 0594ed29d69f5794ccd5e24c5d75c47a7c17f543 | |
| parent | df41dbfd22528b1241668af21a979204b876fb67 (diff) | |
| download | gcc-5d6b1d8ffc4828874ecdb1cde1b794bc3b8d35af.zip gcc-5d6b1d8ffc4828874ecdb1cde1b794bc3b8d35af.tar.gz gcc-5d6b1d8ffc4828874ecdb1cde1b794bc3b8d35af.tar.bz2 | |
fold-const: Handle NON_LVALUE_EXPR in native_encode_initializer [PR114537]
The following testcase is incorrectly rejected. The problem is that
for bit-fields native_encode_initializer expects the corresponding
CONSTRUCTOR elt value must be INTEGER_CST, but that isn't the case
here, it is wrapped into NON_LVALUE_EXPR by maybe_wrap_with_location.
We could STRIP_ANY_LOCATION_WRAPPER as well, but as all we are looking for
is INTEGER_CST inside, just looking through NON_LVALUE_EXPR seems easier.
2024-04-04 Jakub Jelinek <jakub@redhat.com>
PR c++/114537
* fold-const.c (native_encode_initializer): Look through
NON_LVALUE_EXPR if val is INTEGER_CST.
* g++.dg/cpp2a/bit-cast16.C: New test.
(cherry picked from commit 1baec8deb014b8a7da58879a407a4c00cdeb5a09)
| -rw-r--r-- | gcc/fold-const.c | 2 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp2a/bit-cast16.C | 16 |
2 files changed, 18 insertions, 0 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 97f77da..8ca6ba8 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -8402,6 +8402,8 @@ native_encode_initializer (tree init, unsigned char *ptr, int len, if (BYTES_BIG_ENDIAN != WORDS_BIG_ENDIAN) return 0; + if (TREE_CODE (val) == NON_LVALUE_EXPR) + val = TREE_OPERAND (val, 0); if (TREE_CODE (val) != INTEGER_CST) return 0; diff --git a/gcc/testsuite/g++.dg/cpp2a/bit-cast16.C b/gcc/testsuite/g++.dg/cpp2a/bit-cast16.C new file mode 100644 index 0000000..d298af6 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/bit-cast16.C @@ -0,0 +1,16 @@ +// PR c++/114537 +// { dg-do compile { target c++20 } } + +namespace std { +template<typename T, typename F> +constexpr T +bit_cast (const F& f) noexcept +{ + return __builtin_bit_cast (T, f); +} +} + +struct A { signed char b : 1 = 0; signed char c : 7 = 0; }; +struct D { unsigned char e; }; +constexpr unsigned char f = std::bit_cast<D> (A{}).e; +static_assert (f == 0); |