Subjectively speaking, using char8_t instead of char shouldn’t feel like a regression. So yes, making the builtin mem* functions work with char8_t again seems right. As for strlen, I can see arguments either way. Personally, if you’re concerned about clever macros, then I’d make the overload only visible in C++20 mode where char8_t was introduced.
-- Sent from my iPhone > On Apr 5, 2020, at 18:18, Richard Smith <rich...@metafoo.co.uk> wrote: > > >> On Sun, 5 Apr 2020 at 14:44, David Zarzycki via cfe-commits >> <cfe-commits@lists.llvm.org> wrote: > >> We have overloaded builtins. Can that not solve __builtin_strlen? > > I suppose it could, but we generally want __builtin_<libfunc> to behave the > same as <libfunc>. (The difference would not be visible most of the time, but > there's enough pre-existing use of __builtin_strlen through "clever" macros > and the like that I'd be worried that this would break something important.) > Maybe we should just make the mem* functions work again for char8_t; then you > can use __builtin_memchr(p, 0) - p as an optimized compile-time strlen. > >> -- >> Sent from my iPhone >> >>>> On Apr 5, 2020, at 14:53, Richard Smith <rich...@metafoo.co.uk> wrote: >>>> >>> >>> Thanks. We need to figure out what the right way to support char8_t with >>> string builtins is. These ones could work in principle, whereas things like >>> __builtin_strlen would never work because they take operands of the wrong >>> types (and we can't cast const char8_t* -> const char* in a constant >>> expression). >>> >>>> On Sun, 5 Apr 2020 at 04:14, David Zarzycki via cfe-commits >>>> <cfe-commits@lists.llvm.org> wrote: >>>> Hi Richard, >>>> >>>> I'm going to commit a narrow fix to clang to make the libcxx test suite >>>> pass again by allowing char8_t again. If you feel that this is the wrong >>>> long-term solution, please help the libcxx folks with whatever adjustments >>>> they need. >>>> >>>> Thanks! >>>> >>>> Dave >>>> >>>> >>>> On Sat, Apr 4, 2020, at 9:55 AM, David Zarzycki via libcxx-dev wrote: >>>> > Hi Richard, >>>> > >>>> > This breaks libcxx. Can we please revert this or is a quick fix to >>>> > libcxx possible? >>>> > >>>> > >>>> > FAIL: libc++ :: >>>> > std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/compare.pass.cpp >>>> > (58624 of 62672) >>>> > ******************** TEST 'libc++ :: >>>> > std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/compare.pass.cpp' >>>> > FAILED ******************** >>>> > Command: ['/p/tllvm/bin/clang++', '-o', >>>> > '/tmp/_update_lc/t/projects/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/Output/compare.pass.cpp.o', >>>> > '-x', 'c++', >>>> > '/home/dave/s/lp/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/compare.pass.cpp', >>>> > '-c', '-v', '-Werror=thread-safety', '-std=c++2a', '-include', >>>> > '/home/dave/s/lp/libcxx/test/support/nasty_macros.h', '-nostdinc++', >>>> > '-I/home/dave/s/lp/libcxx/include', >>>> > '-I/tmp/_update_lc/t/projects/libcxx/include/c++build', >>>> > '-D__STDC_FORMAT_MACROS', '-D__STDC_LIMIT_MACROS', >>>> > '-D__STDC_CONSTANT_MACROS', '-I/home/dave/s/lp/libcxx/test/support', >>>> > '-ftemplate-depth=270', '-D_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER', >>>> > '-Wall', '-Wextra', '-Werror', '-Wuser-defined-warnings', '-Wshadow', >>>> > '-Wno-unused-command-line-argument', '-Wno-attributes', >>>> > '-Wno-pessimizing-move', '-Wno-c++11-extensions', >>>> > '-Wno-user-defined-literals', '-Wno-noexcept-type', '-Wsign-compare', >>>> > '-Wunused-variable', '-Wunused-parameter', '-Wunreachable-code', '-c'] >>>> > Exit Code: 1 >>>> > Standard Error: >>>> > -- >>>> > clang version 11.0.0 (https://github.com/llvm/llvm-project.git >>>> > 22127da8f17c03c69231f3631472f7f99ad9cb7f) >>>> > Target: x86_64-unknown-linux-gnu >>>> > Thread model: posix >>>> > InstalledDir: /p/tllvm/bin >>>> > Found candidate GCC installation: /usr/lib/gcc/x86_64-redhat-linux/9 >>>> > Selected GCC installation: /usr/lib/gcc/x86_64-redhat-linux/9 >>>> > Candidate multilib: .;@m64 >>>> > Candidate multilib: 32;@m32 >>>> > Selected multilib: .;@m64 >>>> > (in-process) >>>> > "/p/tllvm/bin/clang-11" -cc1 -triple x86_64-unknown-linux-gnu >>>> > -emit-obj -mrelax-all -disable-free -disable-llvm-verifier >>>> > -discard-value-names -main-file-name compare.pass.cpp >>>> > -mrelocation-model static -mthread-model posix -mframe-pointer=all >>>> > -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables >>>> > -target-cpu x86-64 -dwarf-column-info -fno-split-dwarf-inlining >>>> > -debugger-tuning=gdb -v -nostdinc++ -resource-dir >>>> > /p/tllvm/lib64/clang/11.0.0 -include >>>> > /home/dave/s/lp/libcxx/test/support/nasty_macros.h -I >>>> > /home/dave/s/lp/libcxx/include -I >>>> > /tmp/_update_lc/t/projects/libcxx/include/c++build -D >>>> > __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -D __STDC_CONSTANT_MACROS >>>> > -I /home/dave/s/lp/libcxx/test/support -D >>>> > _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER -internal-isystem >>>> > /usr/local/include -internal-isystem >>>> > /p/tllvm/lib64/clang/11.0.0/include -internal-externc-isystem /include >>>> > -internal-externc-isystem /usr/include -Werror=thread-safety -Wall >>>> > -Wextra -Werror -Wuser-defined-warnings -Wshadow >>>> > -Wno-unused-command-line-argument -Wno-attributes -Wno-pessimizing-move >>>> > -Wno-c++11-extensions -Wno-user-defined-literals -Wno-noexcept-type >>>> > -Wsign-compare -Wunused-variable -Wunused-parameter -Wunreachable-code >>>> > -std=c++2a -fdeprecated-macro -fdebug-compilation-dir >>>> > /tmp/_update_lc/t/projects/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t >>>> > -ftemplate-depth 270 -ferror-limit 19 -fgnuc-version=4.2.1 >>>> > -fno-implicit-modules -fcxx-exceptions -fexceptions -faddrsig -o >>>> > /tmp/_update_lc/t/projects/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/Output/compare.pass.cpp.o >>>> > -x c++ >>>> > /home/dave/s/lp/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/compare.pass.cpp >>>> > clang -cc1 version 11.0.0 based upon LLVM 11.0.0git default target >>>> > x86_64-unknown-linux-gnu >>>> > ignoring nonexistent directory "/include" >>>> > #include "..." search starts here: >>>> > #include <...> search starts here: >>>> > /home/dave/s/lp/libcxx/include >>>> > /tmp/_update_lc/t/projects/libcxx/include/c++build >>>> > /home/dave/s/lp/libcxx/test/support >>>> > /usr/local/include >>>> > /p/tllvm/lib64/clang/11.0.0/include >>>> > /usr/include >>>> > End of search list. >>>> > /home/dave/s/lp/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/compare.pass.cpp:53:19: >>>> > error: static_assert expression is not an integral constant expression >>>> > static_assert(test_constexpr(), "" ); >>>> > ^~~~~~~~~~~~~~~~ >>>> > /home/dave/s/lp/libcxx/include/__string:662:12: note: constant >>>> > evaluation of '__builtin_memcmp' between arrays of types 'const >>>> > char8_t' and 'const char8_t' is not supported; only arrays of narrow >>>> > character types can be compared >>>> > return __builtin_memcmp(__s1, __s2, __n); >>>> > ^ >>>> > /home/dave/s/lp/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/compare.pass.cpp:24:12: >>>> > note: in call to 'compare(&u8"123"[0], &u8"223"[0], 3)' >>>> > return std::char_traits<char8_t>::compare(u8"123", u8"223", 3) < 0 >>>> > ^ >>>> > /home/dave/s/lp/libcxx/test/std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/compare.pass.cpp:53:19: >>>> > note: in call to 'test_constexpr()' >>>> > static_assert(test_constexpr(), "" ); >>>> > ^ >>>> > 1 error generated. >>>> > -- >>>> > >>>> > Compilation failed unexpectedly! >>>> > ******************** >>>> > >>>> > Testing Time: 135.49s >>>> > ******************** >>>> > Failing Tests (1): >>>> > libc++ :: >>>> > std/strings/char.traits/char.traits.specializations/char.traits.specializations.char8_t/compare.pass.cpp >>>> > >>>> > Expected Passes : 45503 >>>> > Expected Failures : 118 >>>> > Unsupported Tests : 17050 >>>> > Unexpected Failures: 1 >>>> > >>>> > >>>> > On Fri, Apr 3, 2020, at 9:26 PM, Richard Smith via cfe-commits wrote: >>>> > > >>>> > > Author: Richard Smith >>>> > > Date: 2020-04-03T18:26:14-07:00 >>>> > > New Revision: 4ede8879924c08ae5b495d3f421c167d822a60be >>>> > > >>>> > > URL: >>>> > > https://github.com/llvm/llvm-project/commit/4ede8879924c08ae5b495d3f421c167d822a60be >>>> > > DIFF: >>>> > > https://github.com/llvm/llvm-project/commit/4ede8879924c08ae5b495d3f421c167d822a60be.diff >>>> > > >>>> > > LOG: PR45402: Make the restrictions on constant evaluation of memcmp >>>> > > and >>>> > > memchr consistent and comprehensible, and document them. >>>> > > >>>> > > We previously allowed evaluation of memcmp on arrays of integers of any >>>> > > size, so long as the call evaluated to 0, and allowed evaluation of >>>> > > memchr on any array of integral type of size 1 (including enums). The >>>> > > purpose of constant-evaluating these builtins is only to support >>>> > > constexpr std::char_traits, so we now consistently allow them on arrays >>>> > > of (possibly signed or unsigned) char only. >>>> > > >>>> > > Added: >>>> > > >>>> > > >>>> > > Modified: >>>> > > clang/docs/LanguageExtensions.rst >>>> > > clang/include/clang/Basic/DiagnosticASTKinds.td >>>> > > clang/lib/AST/ExprConstant.cpp >>>> > > clang/test/SemaCXX/constexpr-string.cpp >>>> > > >>>> > > Removed: >>>> > > >>>> > > >>>> > > >>>> > > ################################################################################ >>>> > > diff --git a/clang/docs/LanguageExtensions.rst >>>> > > b/clang/docs/LanguageExtensions.rst >>>> > > index 558ce7dee653..6dcfd1a49f06 100644 >>>> > > --- a/clang/docs/LanguageExtensions.rst >>>> > > +++ b/clang/docs/LanguageExtensions.rst >>>> > > @@ -2333,10 +2333,11 @@ String builtins >>>> > > --------------- >>>> > > >>>> > > Clang provides constant expression evaluation support for builtins >>>> > > forms of >>>> > > -the following functions from the C standard library ``<string.h>`` >>>> > > header: >>>> > > +the following functions from the C standard library headers >>>> > > +``<string.h>`` and ``<wchar.h>``: >>>> > > >>>> > > * ``memchr`` >>>> > > -* ``memcmp`` >>>> > > +* ``memcmp`` (and its deprecated BSD / POSIX alias ``bcmp``) >>>> > > * ``strchr`` >>>> > > * ``strcmp`` >>>> > > * ``strlen`` >>>> > > @@ -2366,7 +2367,11 @@ In addition to the above, one further builtin >>>> > > is >>>> > > provided: >>>> > > constant expressions in C++11 onwards (where a cast from ``void*`` to >>>> > > ``char*`` >>>> > > is disallowed in general). >>>> > > >>>> > > -Support for constant expression evaluation for the above builtins be >>>> > > detected >>>> > > +Constant evaluation support for the ``__builtin_mem*`` functions is >>>> > > provided >>>> > > +only for arrays of ``char``, ``signed char``, or ``unsigned char``, >>>> > > despite >>>> > > +these functions accepting an argument of type ``const void*``. >>>> > > + >>>> > > +Support for constant expression evaluation for the above builtins can >>>> > > be detected >>>> > > with ``__has_feature(cxx_constexpr_string_builtins)``. >>>> > > >>>> > > Memory builtins >>>> > > @@ -2386,6 +2391,25 @@ more information. >>>> > > >>>> > > Note that the `size` argument must be a compile time constant. >>>> > > >>>> > > +Clang provides constant expression evaluation support for builtin >>>> > > forms of the >>>> > > +following functions from the C standard library headers >>>> > > +``<string.h>`` and ``<wchar.h>``: >>>> > > + >>>> > > +* ``memcpy`` >>>> > > +* ``memmove`` >>>> > > +* ``wmemcpy`` >>>> > > +* ``wmemmove`` >>>> > > + >>>> > > +In each case, the builtin form has the name of the C library function >>>> > > prefixed >>>> > > +by ``__builtin_``. >>>> > > + >>>> > > +Constant evaluation support is only provided when the source and >>>> > > destination >>>> > > +are pointers to arrays with the same trivially copyable element type, >>>> > > and the >>>> > > +given size is an exact multiple of the element size that is no >>>> > > greater >>>> > > than >>>> > > +the number of elements accessible through the source and destination >>>> > > operands. >>>> > > + >>>> > > +Constant evaluation support is not yet provided for >>>> > > ``__builtin_memcpy_inline``. >>>> > > + >>>> > > Atomic Min/Max builtins with memory ordering >>>> > > -------------------------------------------- >>>> > > >>>> > > >>>> > > diff --git a/clang/include/clang/Basic/DiagnosticASTKinds.td >>>> > > b/clang/include/clang/Basic/DiagnosticASTKinds.td >>>> > > index 544573edffdf..a1415f9ec0e1 100644 >>>> > > --- a/clang/include/clang/Basic/DiagnosticASTKinds.td >>>> > > +++ b/clang/include/clang/Basic/DiagnosticASTKinds.td >>>> > > @@ -244,6 +244,12 @@ def note_constexpr_unsupported_unsized_array : >>>> > > Note< >>>> > > def note_constexpr_unsized_array_indexed : Note< >>>> > > "indexing of array without known bound is not allowed " >>>> > > "in a constant expression">; >>>> > > +def note_constexpr_memcmp_unsupported : Note< >>>> > > + "constant evaluation of %0 between arrays of types %1 and %2 " >>>> > > + "is not supported; only arrays of narrow character types can be >>>> > > compared">; >>>> > > +def note_constexpr_memchr_unsupported : Note< >>>> > > + "constant evaluation of %0 on array of type %1 " >>>> > > + "is not supported; only arrays of narrow character types can be >>>> > > searched">; >>>> > > def note_constexpr_memcpy_null : Note< >>>> > > "%select{source|destination}2 of " >>>> > > "'%select{%select{memcpy|wmemcpy}1|%select{memmove|wmemmove}1}0' " >>>> > > >>>> > > diff --git a/clang/lib/AST/ExprConstant.cpp >>>> > > b/clang/lib/AST/ExprConstant.cpp >>>> > > index c6e1cc7b67df..a83b2e24e17f 100644 >>>> > > --- a/clang/lib/AST/ExprConstant.cpp >>>> > > +++ b/clang/lib/AST/ExprConstant.cpp >>>> > > @@ -8469,8 +8469,12 @@ bool >>>> > > PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, >>>> > > } >>>> > > // Give up on byte-oriented matching against multibyte elements. >>>> > > // FIXME: We can compare the bytes in the correct order. >>>> > > - if (IsRawByte && Info.Ctx.getTypeSizeInChars(CharTy) != >>>> > > CharUnits::One()) >>>> > > + if (IsRawByte && !CharTy->isCharType()) { >>>> > > + Info.FFDiag(E, diag::note_constexpr_memchr_unsupported) >>>> > > + << (std::string("'") + >>>> > > Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'") >>>> > > + << CharTy; >>>> > > return false; >>>> > > + } >>>> > > // Figure out what value we're actually looking for (after >>>> > > converting to >>>> > > // the corresponding unsigned type if necessary). >>>> > > uint64_t DesiredVal; >>>> > > @@ -8586,6 +8590,7 @@ bool >>>> > > PointerExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, >>>> > > QualType T = Dest.Designator.getType(Info.Ctx); >>>> > > QualType SrcT = Src.Designator.getType(Info.Ctx); >>>> > > if (!Info.Ctx.hasSameUnqualifiedType(T, SrcT)) { >>>> > > + // FIXME: Consider using our bit_cast implementation to support >>>> > > this. >>>> > > Info.FFDiag(E, diag::note_constexpr_memcpy_type_pun) << Move << >>>> > > SrcT << T; >>>> > > return false; >>>> > > } >>>> > > @@ -11149,6 +11154,16 @@ bool >>>> > > IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, >>>> > > CharTy1, E->getArg(0)->getType()->getPointeeType()) && >>>> > > Info.Ctx.hasSameUnqualifiedType(CharTy1, CharTy2))); >>>> > > >>>> > > + // For memcmp, allow comparing any arrays of '[[un]signed] char', >>>> > > + // but no other types. >>>> > > + if (IsRawByte && !(CharTy1->isCharType() && >>>> > > CharTy2->isCharType())) { >>>> > > + // FIXME: Consider using our bit_cast implementation to support >>>> > > this. >>>> > > + Info.FFDiag(E, diag::note_constexpr_memcmp_unsupported) >>>> > > + << (std::string("'") + >>>> > > Info.Ctx.BuiltinInfo.getName(BuiltinOp) + "'") >>>> > > + << CharTy1 << CharTy2; >>>> > > + return false; >>>> > > + } >>>> > > + >>>> > > const auto &ReadCurElems = [&](APValue &Char1, APValue &Char2) { >>>> > > return handleLValueToRValueConversion(Info, E, CharTy1, >>>> > > String1, >>>> > > Char1) && >>>> > > handleLValueToRValueConversion(Info, E, CharTy2, >>>> > > String2, >>>> > > Char2) && >>>> > > @@ -11159,57 +11174,6 @@ bool >>>> > > IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, >>>> > > HandleLValueArrayAdjustment(Info, E, String2, CharTy2, >>>> > > 1); >>>> > > }; >>>> > > >>>> > > - if (IsRawByte) { >>>> > > - uint64_t BytesRemaining = MaxLength; >>>> > > - // Pointers to const void may point to objects of incomplete >>>> > > type. >>>> > > - if (CharTy1->isIncompleteType()) { >>>> > > - Info.FFDiag(E, diag::note_constexpr_ltor_incomplete_type) << >>>> > > CharTy1; >>>> > > - return false; >>>> > > - } >>>> > > - if (CharTy2->isIncompleteType()) { >>>> > > - Info.FFDiag(E, diag::note_constexpr_ltor_incomplete_type) << >>>> > > CharTy2; >>>> > > - return false; >>>> > > - } >>>> > > - uint64_t CharTy1Width{Info.Ctx.getTypeSize(CharTy1)}; >>>> > > - CharUnits CharTy1Size = >>>> > > Info.Ctx.toCharUnitsFromBits(CharTy1Width); >>>> > > - // Give up on comparing between elements with disparate widths. >>>> > > - if (CharTy1Size != Info.Ctx.getTypeSizeInChars(CharTy2)) >>>> > > - return false; >>>> > > - uint64_t BytesPerElement = CharTy1Size.getQuantity(); >>>> > > - assert(BytesRemaining && "BytesRemaining should not be zero: >>>> > > the >>>> > > " >>>> > > - "following loop considers at least one >>>> > > element"); >>>> > > - while (true) { >>>> > > - APValue Char1, Char2; >>>> > > - if (!ReadCurElems(Char1, Char2)) >>>> > > - return false; >>>> > > - // We have compatible in-memory widths, but a possible type >>>> > > and >>>> > > - // (for `bool`) internal representation mismatch. >>>> > > - // Assuming two's complement representation, including 0 for >>>> > > `false` and >>>> > > - // 1 for `true`, we can check an appropriate number of >>>> > > elements for >>>> > > - // equality even if they are not byte-sized. >>>> > > - APSInt Char1InMem = Char1.getInt().extOrTrunc(CharTy1Width); >>>> > > - APSInt Char2InMem = Char2.getInt().extOrTrunc(CharTy1Width); >>>> > > - if (Char1InMem.ne(Char2InMem)) { >>>> > > - // If the elements are byte-sized, then we can produce a >>>> > > three-way >>>> > > - // comparison result in a straightforward manner. >>>> > > - if (BytesPerElement == 1u) { >>>> > > - // memcmp always compares unsigned chars. >>>> > > - return Success(Char1InMem.ult(Char2InMem) ? -1 : 1, E); >>>> > > - } >>>> > > - // The result is byte-order sensitive, and we have >>>> > > multibyte >>>> > > elements. >>>> > > - // FIXME: We can compare the remaining bytes in the correct >>>> > > order. >>>> > > - return false; >>>> > > - } >>>> > > - if (!AdvanceElems()) >>>> > > - return false; >>>> > > - if (BytesRemaining <= BytesPerElement) >>>> > > - break; >>>> > > - BytesRemaining -= BytesPerElement; >>>> > > - } >>>> > > - // Enough elements are equal to account for the memcmp limit. >>>> > > - return Success(0, E); >>>> > > - } >>>> > > - >>>> > > bool StopAtNull = >>>> > > (BuiltinOp != Builtin::BImemcmp && BuiltinOp != >>>> > > Builtin::BIbcmp && >>>> > > BuiltinOp != Builtin::BIwmemcmp && >>>> > > @@ -11227,7 +11191,7 @@ bool >>>> > > IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E, >>>> > > APValue Char1, Char2; >>>> > > if (!ReadCurElems(Char1, Char2)) >>>> > > return false; >>>> > > - if (Char1.getInt() != Char2.getInt()) { >>>> > > + if (Char1.getInt().ne(Char2.getInt())) { >>>> > > if (IsWide) // wmemcmp compares with wchar_t signedness. >>>> > > return Success(Char1.getInt() < Char2.getInt() ? -1 : 1, E); >>>> > > // memcmp always compares unsigned chars. >>>> > > >>>> > > diff --git a/clang/test/SemaCXX/constexpr-string.cpp >>>> > > b/clang/test/SemaCXX/constexpr-string.cpp >>>> > > index f540be8f8e5b..79ac3bf2cc4d 100644 >>>> > > --- a/clang/test/SemaCXX/constexpr-string.cpp >>>> > > +++ b/clang/test/SemaCXX/constexpr-string.cpp >>>> > > @@ -47,7 +47,7 @@ extern "C" { >>>> > > extern wchar_t *wmemmove(wchar_t *d, const wchar_t *s, size_t n); >>>> > > } >>>> > > >>>> > > -# 45 "SemaCXX/constexpr-string.cpp" 2 >>>> > > +# 51 "SemaCXX/constexpr-string.cpp" 2 >>>> > > namespace Strlen { >>>> > > constexpr int n = __builtin_strlen("hello"); // ok >>>> > > static_assert(n == 5); >>>> > > @@ -121,13 +121,13 @@ namespace StrcmpEtc { >>>> > > extern struct Incomplete incomplete; >>>> > > static_assert(__builtin_memcmp(&incomplete, "", 0u) == 0); >>>> > > static_assert(__builtin_memcmp("", &incomplete, 0u) == 0); >>>> > > - static_assert(__builtin_memcmp(&incomplete, "", 1u) == 42); // >>>> > > expected-error {{not an integral constant}} expected-note {{read of >>>> > > incomplete type 'struct Incomplete'}} >>>> > > - static_assert(__builtin_memcmp("", &incomplete, 1u) == 42); // >>>> > > expected-error {{not an integral constant}} expected-note {{read of >>>> > > incomplete type 'struct Incomplete'}} >>>> > > + static_assert(__builtin_memcmp(&incomplete, "", 1u) == 42); // >>>> > > expected-error {{not an integral constant}} expected-note {{not >>>> > > supported}} >>>> > > + static_assert(__builtin_memcmp("", &incomplete, 1u) == 42); // >>>> > > expected-error {{not an integral constant}} expected-note {{not >>>> > > supported}} >>>> > > >>>> > > static_assert(__builtin_bcmp(&incomplete, "", 0u) == 0); >>>> > > static_assert(__builtin_bcmp("", &incomplete, 0u) == 0); >>>> > > - static_assert(__builtin_bcmp(&incomplete, "", 1u) == 42); // >>>> > > expected-error {{not an integral constant}} expected-note {{read of >>>> > > incomplete type 'struct Incomplete'}} >>>> > > - static_assert(__builtin_bcmp("", &incomplete, 1u) == 42); // >>>> > > expected-error {{not an integral constant}} expected-note {{read of >>>> > > incomplete type 'struct Incomplete'}} >>>> > > + static_assert(__builtin_bcmp(&incomplete, "", 1u) == 42); // >>>> > > expected-error {{not an integral constant}} expected-note {{not >>>> > > supported}} >>>> > > + static_assert(__builtin_bcmp("", &incomplete, 1u) == 42); // >>>> > > expected-error {{not an integral constant}} expected-note {{not >>>> > > supported}} >>>> > > >>>> > > constexpr unsigned char ku00fe00[] = {0x00, 0xfe, 0x00}; >>>> > > constexpr unsigned char ku00feff[] = {0x00, 0xfe, 0xff}; >>>> > > @@ -155,11 +155,11 @@ namespace StrcmpEtc { >>>> > > >>>> > > struct Bool3Tuple { bool bb[3]; }; >>>> > > constexpr Bool3Tuple kb000100 = {{false, true, false}}; >>>> > > - static_assert(sizeof(bool) != 1u || __builtin_memcmp(ks00fe00, >>>> > > kb000100.bb, 1) == 0); >>>> > > - static_assert(sizeof(bool) != 1u || __builtin_memcmp(ks00fe00, >>>> > > kb000100.bb, 2) == 1); >>>> > > + static_assert(sizeof(bool) != 1u || __builtin_memcmp(ks00fe00, >>>> > > kb000100.bb, 1) == 0); // expected-error {{constant}} expected-note >>>> > > {{not supported}} >>>> > > + static_assert(sizeof(bool) != 1u || __builtin_memcmp(ks00fe00, >>>> > > kb000100.bb, 2) == 1); // expected-error {{constant}} expected-note >>>> > > {{not supported}} >>>> > > >>>> > > - static_assert(sizeof(bool) != 1u || __builtin_bcmp(ks00fe00, >>>> > > kb000100.bb, 1) == 0); >>>> > > - static_assert(sizeof(bool) != 1u || __builtin_bcmp(ks00fe00, >>>> > > kb000100.bb, 2) != 0); >>>> > > + static_assert(sizeof(bool) != 1u || __builtin_bcmp(ks00fe00, >>>> > > kb000100.bb, 1) == 0); // expected-error {{constant}} expected-note >>>> > > {{not supported}} >>>> > > + static_assert(sizeof(bool) != 1u || __builtin_bcmp(ks00fe00, >>>> > > kb000100.bb, 2) != 0); // expected-error {{constant}} expected-note >>>> > > {{not supported}} >>>> > > >>>> > > constexpr long ksl[] = {0, -1}; >>>> > > constexpr unsigned int kui[] = {0, 0u - 1}; >>>> > > @@ -173,25 +173,25 @@ namespace StrcmpEtc { >>>> > > return nullptr; >>>> > > } >>>> > > } >>>> > > - static_assert(__builtin_memcmp(ksl, kuSizeofLong(), sizeof(long) - >>>> > > 1) == 0); >>>> > > - static_assert(__builtin_memcmp(ksl, kuSizeofLong(), sizeof(long) + >>>> > > 0) == 0); >>>> > > - static_assert(__builtin_memcmp(ksl, kuSizeofLong(), sizeof(long) + >>>> > > 1) == 0); >>>> > > - static_assert(__builtin_memcmp(ksl, kuSizeofLong(), 2*sizeof(long) >>>> > > - >>>> > > 1) == 0); >>>> > > - static_assert(__builtin_memcmp(ksl, kuSizeofLong(), 2*sizeof(long) >>>> > > + >>>> > > 0) == 0); >>>> > > - static_assert(__builtin_memcmp(ksl, kuSizeofLong(), 2*sizeof(long) >>>> > > + >>>> > > 1) == 42); // expected-error {{not an integral constant}} >>>> > > expected-note >>>> > > {{dereferenced one-past-the-end}} >>>> > > - static_assert(__builtin_memcmp(ksl + 1, kuSizeofLong() + 1, >>>> > > sizeof(long) - 1) == 0); >>>> > > - static_assert(__builtin_memcmp(ksl + 1, kuSizeofLong() + 1, >>>> > > sizeof(long) + 0) == 0); >>>> > > - static_assert(__builtin_memcmp(ksl + 1, kuSizeofLong() + 1, >>>> > > sizeof(long) + 1) == 42); // expected-error {{not an integral >>>> > > constant}} expected-note {{dereferenced one-past-the-end}} >>>> > > - >>>> > > - static_assert(__builtin_bcmp(ksl, kuSizeofLong(), sizeof(long) - 1) >>>> > > == 0); >>>> > > - static_assert(__builtin_bcmp(ksl, kuSizeofLong(), sizeof(long) + 0) >>>> > > == 0); >>>> > > - static_assert(__builtin_bcmp(ksl, kuSizeofLong(), sizeof(long) + 1) >>>> > > == 0); >>>> > > - static_assert(__builtin_bcmp(ksl, kuSizeofLong(), 2*sizeof(long) - >>>> > > 1) == 0); >>>> > > - static_assert(__builtin_bcmp(ksl, kuSizeofLong(), 2*sizeof(long) + >>>> > > 0) == 0); >>>> > > - static_assert(__builtin_bcmp(ksl, kuSizeofLong(), 2*sizeof(long) + >>>> > > 1) == 42); // expected-error {{not an integral constant}} >>>> > > expected-note >>>> > > {{dereferenced one-past-the-end}} >>>> > > - static_assert(__builtin_bcmp(ksl + 1, kuSizeofLong() + 1, >>>> > > sizeof(long) - 1) == 0); >>>> > > - static_assert(__builtin_bcmp(ksl + 1, kuSizeofLong() + 1, >>>> > > sizeof(long) + 0) == 0); >>>> > > - static_assert(__builtin_bcmp(ksl + 1, kuSizeofLong() + 1, >>>> > > sizeof(long) + 1) == 42); // expected-error {{not an integral >>>> > > constant}} expected-note {{dereferenced one-past-the-end}} >>>> > > + static_assert(__builtin_memcmp(ksl, kuSizeofLong(), sizeof(long) - >>>> > > 1) == 0); // expected-error {{constant}} expected-note {{not >>>> > > supported}} >>>> > > + static_assert(__builtin_memcmp(ksl, kuSizeofLong(), sizeof(long) + >>>> > > 0) == 0); // expected-error {{constant}} expected-note {{not >>>> > > supported}} >>>> > > + static_assert(__builtin_memcmp(ksl, kuSizeofLong(), sizeof(long) + >>>> > > 1) == 0); // expected-error {{constant}} expected-note {{not >>>> > > supported}} >>>> > > + static_assert(__builtin_memcmp(ksl, kuSizeofLong(), 2*sizeof(long) >>>> > > - >>>> > > 1) == 0); // expected-error {{constant}} expected-note {{not >>>> > > supported}} >>>> > > + static_assert(__builtin_memcmp(ksl, kuSizeofLong(), 2*sizeof(long) >>>> > > + >>>> > > 0) == 0); // expected-error {{constant}} expected-note {{not >>>> > > supported}} >>>> > > + static_assert(__builtin_memcmp(ksl, kuSizeofLong(), 2*sizeof(long) >>>> > > + >>>> > > 1) == 42); // expected-error {{constant}} expected-note {{not >>>> > > supported}} >>>> > > + static_assert(__builtin_memcmp(ksl + 1, kuSizeofLong() + 1, >>>> > > sizeof(long) - 1) == 0); // expected-error {{constant}} expected-note >>>> > > {{not supported}} >>>> > > + static_assert(__builtin_memcmp(ksl + 1, kuSizeofLong() + 1, >>>> > > sizeof(long) + 0) == 0); // expected-error {{constant}} expected-note >>>> > > {{not supported}} >>>> > > + static_assert(__builtin_memcmp(ksl + 1, kuSizeofLong() + 1, >>>> > > sizeof(long) + 1) == 42); // expected-error {{constant}} expected-note >>>> > > {{not supported}} >>>> > > + >>>> > > + static_assert(__builtin_bcmp(ksl, kuSizeofLong(), sizeof(long) - 1) >>>> > > == 0); // expected-error {{constant}} expected-note {{not supported}} >>>> > > + static_assert(__builtin_bcmp(ksl, kuSizeofLong(), sizeof(long) + 0) >>>> > > == 0); // expected-error {{constant}} expected-note {{not supported}} >>>> > > + static_assert(__builtin_bcmp(ksl, kuSizeofLong(), sizeof(long) + 1) >>>> > > == 0); // expected-error {{constant}} expected-note {{not supported}} >>>> > > + static_assert(__builtin_bcmp(ksl, kuSizeofLong(), 2*sizeof(long) - >>>> > > 1) == 0); // expected-error {{constant}} expected-note {{not >>>> > > supported}} >>>> > > + static_assert(__builtin_bcmp(ksl, kuSizeofLong(), 2*sizeof(long) + >>>> > > 0) == 0); // expected-error {{constant}} expected-note {{not >>>> > > supported}} >>>> > > + static_assert(__builtin_bcmp(ksl, kuSizeofLong(), 2*sizeof(long) + >>>> > > 1) == 42); // expected-error {{constant}} expected-note {{not >>>> > > supported}} >>>> > > + static_assert(__builtin_bcmp(ksl + 1, kuSizeofLong() + 1, >>>> > > sizeof(long) - 1) == 0); // expected-error {{constant}} expected-note >>>> > > {{not supported}} >>>> > > + static_assert(__builtin_bcmp(ksl + 1, kuSizeofLong() + 1, >>>> > > sizeof(long) + 0) == 0); // expected-error {{constant}} expected-note >>>> > > {{not supported}} >>>> > > + static_assert(__builtin_bcmp(ksl + 1, kuSizeofLong() + 1, >>>> > > sizeof(long) + 1) == 42); // expected-error {{constant}} expected-note >>>> > > {{not supported}} >>>> > > >>>> > > constexpr int a = strcmp("hello", "world"); // expected-error >>>> > > {{constant expression}} expected-note {{non-constexpr function >>>> > > 'strcmp' >>>> > > cannot be used in a constant expression}} >>>> > > constexpr int b = strncmp("hello", "world", 3); // expected-error >>>> > > {{constant expression}} expected-note {{non-constexpr function >>>> > > 'strncmp' cannot be used in a constant expression}} >>>> > > @@ -385,14 +385,14 @@ namespace StrchrEtc { >>>> > > enum class E : unsigned char {}; >>>> > > struct EPair { E e, f; }; >>>> > > constexpr EPair ee{E{240}}; >>>> > > - static_assert(__builtin_memchr(&ee.e, 240, 1) == &ee.e); >>>> > > + static_assert(__builtin_memchr(&ee.e, 240, 1) == &ee.e); // >>>> > > expected-error {{constant}} expected-note {{not supported}} >>>> > > >>>> > > constexpr bool kBool[] = {false, true, false}; >>>> > > constexpr const bool *const kBoolPastTheEndPtr = kBool + 3; >>>> > > - static_assert(sizeof(bool) != 1u || >>>> > > __builtin_memchr(kBoolPastTheEndPtr - 3, 1, 99) == kBool + 1); >>>> > > - static_assert(sizeof(bool) != 1u || __builtin_memchr(kBool + 1, 0, >>>> > > 99) == kBoolPastTheEndPtr - 1); >>>> > > - static_assert(sizeof(bool) != 1u || >>>> > > __builtin_memchr(kBoolPastTheEndPtr - 3, -1, 3) == nullptr); >>>> > > - static_assert(sizeof(bool) != 1u || >>>> > > __builtin_memchr(kBoolPastTheEndPtr, 0, 1) == nullptr); // >>>> > > expected-error {{not an integral constant}} expected-note >>>> > > {{dereferenced one-past-the-end}} >>>> > > + static_assert(sizeof(bool) != 1u || >>>> > > __builtin_memchr(kBoolPastTheEndPtr - 3, 1, 99) == kBool + 1); // >>>> > > expected-error {{constant}} expected-note {{not supported}} >>>> > > + static_assert(sizeof(bool) != 1u || __builtin_memchr(kBool + 1, 0, >>>> > > 99) == kBoolPastTheEndPtr - 1); // expected-error {{constant}} >>>> > > expected-note {{not supported}} >>>> > > + static_assert(sizeof(bool) != 1u || >>>> > > __builtin_memchr(kBoolPastTheEndPtr - 3, -1, 3) == nullptr); // >>>> > > expected-error {{constant}} expected-note {{not supported}} >>>> > > + static_assert(sizeof(bool) != 1u || >>>> > > __builtin_memchr(kBoolPastTheEndPtr, 0, 1) == nullptr); // >>>> > > expected-error {{constant}} expected-note {{not supported}} >>>> > > >>>> > > static_assert(__builtin_char_memchr(kStr, 'a', 0) == nullptr); >>>> > > static_assert(__builtin_char_memchr(kStr, 'a', 1) == kStr); >>>> > > >>>> > > >>>> > > >>>> > > _______________________________________________ >>>> > > cfe-commits mailing list >>>> > > cfe-commits@lists.llvm.org >>>> > > https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >>>> > > >>>> > _______________________________________________ >>>> > libcxx-dev mailing list >>>> > libcxx-...@lists.llvm.org >>>> > https://lists.llvm.org/cgi-bin/mailman/listinfo/libcxx-dev >>>> > >>>> _______________________________________________ >>>> cfe-commits mailing list >>>> cfe-commits@lists.llvm.org >>>> https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >> _______________________________________________ >> cfe-commits mailing list >> cfe-commits@lists.llvm.org >> https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
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