markus@x4 clang_bugs % cat test3.ii
[[gnu::fastcall]] void f();

markus@x4 clang_bugs % clang++ -c -std=c++11 test3.ii
test3.ii:1:3: warning: calling convention 'fastcall' ignored for this target [-Wignored-attributes]
[[gnu::fastcall]] void f();
  ^
0  clang-3.4       0x0000000000fc47f2 llvm::sys::PrintStackTrace(_IO_FILE*) + 34
1  clang-3.4       0x0000000000fc43c4
2  libpthread.so.0 0x00007f4b216e2820
3  clang-3.4       0x00000000015f5fe4
4  clang-3.4       0x00000000015fae75 clang::Sema::GetTypeSourceInfoForDeclarator(clang::Declarator&, clang::QualType, clang::TypeSourceInfo*) + 341
5  clang-3.4       0x000000000160554c
6  clang-3.4       0x0000000001607e30 clang::Sema::GetTypeForDeclarator(clang::Declarator&, clang::Scope*) + 352
7  clang-3.4       0x00000000013afdff clang::Sema::HandleDeclarator(clang::Scope*, clang::Declarator&, llvm::MutableArrayRef<clang::TemplateParameterList*>) + 815
8  clang-3.4       0x00000000013b08d5 clang::Sema::ActOnDeclarator(clang::Scope*, clang::Declarator&) + 21
9  clang-3.4       0x0000000001280b19 clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&) + 73
10 clang-3.4       0x000000000128b2bd clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, unsigned int, bool, clang::SourceLocation*, clang::Parser::ForRangeInit*) + 1773
11 clang-3.4       0x00000000012774ad clang::Parser::ParseDeclOrFunctionDefInternal(clang::Parser::ParsedAttributesWithRange&, clang::ParsingDeclSpec&, clang::AccessSpecifier) + 237
12 clang-3.4       0x0000000001277b19
13 clang-3.4       0x0000000001277b4f clang::Parser::ParseDeclarationOrFunctionDefinition(clang::Parser::ParsedAttributesWithRange&, clang::ParsingDeclSpec*, clang::AccessSpecifier) + 31
14 clang-3.4       0x000000000127bc9b clang::Parser::ParseExternalDeclaration(clang::Parser::ParsedAttributesWithRange&, clang::ParsingDeclSpec*) + 267
15 clang-3.4       0x000000000127c572 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&) + 194
16 clang-3.4       0x0000000001271da0 clang::ParseAST(clang::Sema&, bool, bool) + 368
17 clang-3.4       0x00000000011c0da9 clang::FrontendAction::Execute() + 169
18 clang-3.4       0x00000000011a30e8 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 296
19 clang-3.4       0x0000000000fc7d0a clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 1402
20 clang-3.4       0x00000000006dcb88 cc1_main(char const**, char const**, char const*, void*) + 824
21 clang-3.4       0x00000000006c77c9 main + 9193
22 libc.so.6       0x00007f4b210fca75 __libc_start_main + 245
23 clang-3.4       0x00000000006dbdc2
Stack dump:
0.      Program arguments: /usr/local/bin/clang-3.4 -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -mrelax-all -disable-free -disable-llvm-verifier -main-file-name test3.ii -mrelocation-model static -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -coverage-file /var/tmp/clang_bugs/test3.o -resource-dir /usr/local/bin/../lib/clang/3.4 -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /var/tmp/clang_bugs -ferror-limit 19 -fmessage-length 174 -mstackrealign -fobjc-runtime=gcc -fcxx-exceptions -fexceptions -fdiagnostics-show-option -fcolor-diagnostics -vectorize-slp -o test3.o -x c++-cpp-output test3.ii 
1.      test3.ii:1:27: current parser token ';'
clang-3.4: error: unable to execute command: Segmentation fault
clang-3.4: error: clang frontend command failed due to signal (use -v to see invocation)
clang version 3.4 (http://llvm.org/git/clang.git f78bf4a0132a3ea366ba3baadd9d6af26c617d11) (http://llvm.org/git/llvm.git 835e284214c6e920924b5375590e77fd953cbefe)
Target: x86_64-unknown-linux-gnu
Thread model: posix
clang-3.4: note: diag