[LLVMbugs] [Bug 8917] New: clang much slower than gcc compiling CryptoPP sources

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=8917

           Summary: clang much slower than gcc compiling CryptoPP sources
           Product: clang
           Version: trunk
          Platform: Macintosh
        OS/Version: MacOS X
            Status: NEW
          Severity: normal
          Priority: P
         Component: C++
        AssignedTo: unassignedclangbugs at nondot.org
        ReportedBy: mclow at qualcomm.com
                CC: llvmbugs at cs.uiuc.edu, dgregor at apple.com


Created an attachment (id=5965)
 --> (http://llvm.org/bugs/attachment.cgi?id=5965)
preprocessed source code for sha.cpp

When trying to compile CryptoPP <http://www.cryptopp.com>, I noticed that the
compile times were much, much slower than gcc. Some of this is the optimizer,
but there's something going on in the front end, too.

This was done with clang/llvm built from revision 122872

attached file was created via:
      clang++ -Wno-tautological-compare -DNDEBUG -g -DCRYPTOPP_DISABLE_ASM -E
sha.cpp > sha.i

Compare:
$ time clang++ -Wno-tautological-compare -DNDEBUG -g         -arch x86_64 -arch
i386 -DCRYPTOPP_DISABLE_ASM -pipe -fsyntax-only sha.cpp 
real    6.234s
$ time clang++ -Wno-tautological-compare -DNDEBUG -g         -arch x86_64 -arch
i386 -DCRYPTOPP_DISABLE_ASM -pipe -c sha.cpp 
real 7.863s

with:

$ time g++ -DNDEBUG -g -O2 -arch x86_64 -arch i386 -DCRYPTOPP_DISABLE_ASM -pipe
-c sha.cpp 
real 1.662s

-- 
Configure bugmail: http://llvm.org/bugs/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.