[LLVMbugs] [Bug 12521] New: dsputil.c from ffmpeg takes > 13s to compile with -O (1.3s without)

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=12521

             Bug #: 12521
           Summary: dsputil.c from ffmpeg takes > 13s to compile with -O
                    (1.3s without)
           Product: clang
           Version: unspecified
          Platform: PC
        OS/Version: All
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: LLVM Codegen
        AssignedTo: unassignedclangbugs at nondot.org
        ReportedBy: nicolasweber at gmx.de
                CC: llvmbugs at cs.uiuc.edu
    Classification: Unclassified


Created attachment 8370
  --> http://llvm.org/bugs/attachment.cgi?id=8370
repro

Attached is a preprocessed version of ffmpeg's dsputil.c. The file is
comparably small (700kB, 11k lines), but takes a long time to codegen:


hummer:src thakis$ time third_party/llvm-build/Release+Asserts/bin/clang -c
~/dsputil.i 

real    0m1.985s
user    0m1.619s
sys    0m0.082s

hummer:src thakis$ time third_party/llvm-build/Release+Asserts/bin/clang -c -O
~/dsputil.i 

real    0m13.894s
user    0m11.112s
sys    0m0.141s

hummer:src thakis$ time third_party/llvm-build/Release+Asserts/bin/clang -c -O
~/dsputil.i -fsyntax-only

real    0m0.512s
user    0m0.458s
sys    0m0.025s


This is with clang r153589.

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