[LLVMbugs] [Bug 4573] New: excessive code size with X86 backend

bugzilla-daemon at cs.uiuc.edu bugzilla-daemon at cs.uiuc.edu
Fri Jul 17 19:27:27 PDT 2009


           Summary: excessive code size with X86 backend
           Product: new-bugs
           Version: unspecified
          Platform: PC
        OS/Version: OpenBSD
            Status: NEW
          Severity: normal
          Priority: P2
         Component: new bugs
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: jsg at openbsd.org
                CC: llvmbugs at cs.uiuc.edu

When compiling various parts of the OpenBSD kernel there is a significant
increase in code size on many object files, which is likely the cause
of slow compilation speeds.

Such as:
if_spppsubr.o, clang: 124440, gcc335: 48968, gcc424: 49272, llvmgcc: 120400
bwi.o, clang: 164452, gcc335: 99856, gcc424: 101664, llvmgcc: 163172
pciide.o, clang: 90628, gcc335: 74560, gcc424: 77036, llvmgcc: 88160

A full list can be found at
and a summary at

Compile flags used
-Wall -Wstrict-prototypes -Wmissing-prototypes  -Wno-uninitialized -Wno-format
-fno-builtin -fno-zero-initialized-
in-bss  -mno-mmx -mno-sse -mno-sse2 -mno-sse3 -O2 -pipe -nostdinc

Local changes to the llvm tree are ignoring kprintf format attribute/bounded
attribute.  Changed --mcpu default from pentium4 to i486 so floating point code
isn't generated in the kernel.  And some openbsd link target changes I'll be
submitting sometime soon (mostly just libgcc).

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