forked from OSchip/llvm-project
5c562f62a4
I noticed that the following case would compile in Clang but not GCC:
void *x(void) {
void *p = &&foo;
asm goto ("# %0\n\t# %l1":"+r"(p):::foo);
foo:;
return p;
}
Changing the output template above from %l2 would compile in GCC but not
Clang.
This demonstrates that when using tied outputs (say via the "+r" output
constraint), the hidden inputs occur or are numbered BEFORE the labels,
at least with GCC.
In fact, GCC does denote this in its documentation:
https://gcc.gnu.org/onlinedocs/gcc-11.2.0/gcc/Extended-Asm.html#Goto-Labels
> Output operand with constraint modifier ‘+’ is counted as two operands
> because it is considered as one output and one input operand.
For the sake of compatibility, I think it's worthwhile to just make this
change.
It's better to use symbolic names for compatibility (especially now
between released version of Clang that support asm goto with outputs).
ie. %l1 from the above would be %l[foo]. The GCC docs also make this
recommendation.
Also, I cleaned up some cruft in GCCAsmStmt::getNamedOperand. AFAICT,
NumPlusOperands was no longer used, though I couldn't find which commit
didn't clean that up correctly.
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98096
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103640
Link: https://gcc.gnu.org/onlinedocs/gcc-11.2.0/gcc/Extended-Asm.html#Goto-Labels
Reviewed By: void
Differential Revision: https://reviews.llvm.org/D115471
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| .. | ||
| CommandGuide | ||
| DataFlowAnalysisIntroImages | ||
| analyzer | ||
| tools | ||
| APINotes.rst | ||
| AddressSanitizer.rst | ||
| AutomaticReferenceCounting.rst | ||
| Block-ABI-Apple.rst | ||
| BlockLanguageSpec.rst | ||
| CMakeLists.txt | ||
| ClangCheck.rst | ||
| ClangCommandLineReference.rst | ||
| ClangFormat.rst | ||
| ClangFormatStyleOptions.rst | ||
| ClangFormattedStatus.rst | ||
| ClangNvlinkWrapper.rst | ||
| ClangOffloadBundler.rst | ||
| ClangPlugins.rst | ||
| ClangStaticAnalyzer.rst | ||
| ClangTools.rst | ||
| ClangTransformerTutorial.rst | ||
| ConstantInterpreter.rst | ||
| ControlFlowIntegrity.rst | ||
| ControlFlowIntegrityDesign.rst | ||
| CrossCompilation.rst | ||
| DataFlowAnalysisIntro.md | ||
| DataFlowSanitizer.rst | ||
| DataFlowSanitizerDesign.rst | ||
| DriverArchitecture.png | ||
| DriverInternals.rst | ||
| ExternalClangExamples.rst | ||
| FAQ.rst | ||
| HardwareAssistedAddressSanitizerDesign.rst | ||
| HowToSetupToolingForLLVM.rst | ||
| InternalsManual.rst | ||
| IntroductionToTheClangAST.rst | ||
| ItaniumMangleAbiTags.rst | ||
| JSONCompilationDatabase.rst | ||
| LTOVisibility.rst | ||
| LanguageExtensions.rst | ||
| LeakSanitizer.rst | ||
| LibASTImporter.rst | ||
| LibASTMatchers.rst | ||
| LibASTMatchersReference.html | ||
| LibASTMatchersTutorial.rst | ||
| LibFormat.rst | ||
| LibTooling.rst | ||
| MSVCCompatibility.rst | ||
| MatrixTypes.rst | ||
| MemorySanitizer.rst | ||
| Modules.rst | ||
| ObjectiveCLiterals.rst | ||
| OpenCLSupport.rst | ||
| OpenMPSupport.rst | ||
| PCHInternals.rst | ||
| PCHLayout.graffle | ||
| PCHLayout.png | ||
| RAVFrontendAction.rst | ||
| README.txt | ||
| RefactoringEngine.rst | ||
| ReleaseNotes.rst | ||
| SYCLSupport.rst | ||
| SafeStack.rst | ||
| SanitizerCoverage.rst | ||
| SanitizerSpecialCaseList.rst | ||
| SanitizerStats.rst | ||
| ShadowCallStack.rst | ||
| SourceBasedCodeCoverage.rst | ||
| ThinLTO.rst | ||
| ThreadSafetyAnalysis.rst | ||
| ThreadSanitizer.rst | ||
| Toolchain.rst | ||
| Tooling.rst | ||
| UndefinedBehaviorSanitizer.rst | ||
| UsersManual.rst | ||
| conf.py | ||
| doxygen-mainpage.dox | ||
| doxygen.cfg.in | ||
| index.rst | ||
| make.bat | ||
README.txt
See llvm/docs/README.txt