[LLVMbugs] [Bug 23366] New: Incredibly slow compilation of inline-assembly-heavy C++ code

[bugzilla-daemon at llvm.org]

https://llvm.org/bugs/show_bug.cgi?id=23366

            Bug ID: 23366
           Summary: Incredibly slow compilation of inline-assembly-heavy
                    C++ code
           Product: clang
           Version: 3.6
          Hardware: Macintosh
                OS: MacOS X
            Status: NEW
          Severity: normal
          Priority: P
         Component: C++
          Assignee: unassignedclangbugs at nondot.org
          Reporter: johan.overbye at gmail.com
                CC: dgregor at apple.com, llvmbugs at cs.uiuc.edu
    Classification: Unclassified

Created attachment 14263
  --> https://llvm.org/bugs/attachment.cgi?id=14263&action=edit
OS X Activity Monitor sample of the clang process

In our project we have a single C++ file that contains very large amounts of
inline assembly code.

It used to take no noticeable time to compile this (< 1 second), but after
upgrading to LLVM 3.6 (Apple LLVM 6.1 in Xcode), it's taking tens of minutes.
I'm guessing roughly 30 minutes on this MacBook:

2.2 GHz Intel Core i7
8 GB 1333 MHz DDR3

I'm not at liberty to share the code, however after some testing, it looks like
it might be down to just the quantity of inline assembly code.

On profiling the clang process, the function
clang::GCCAsmStmt::AnalyzeAsmString() seems to be doing all the work. Call
stack from OS X Activity Monitor is attached.

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20150428/c3a50e3a/attachment.html>