[Bug c/41175] -Os generates significantly larger code

[Bug c/41175] -Os generates significantly larger code

[galak at kernel dot crashing dot org]

------- Comment #1 from galak at kernel dot crashing dot org  2009-08-26 14:18 -------
Created an attachment (id=18428)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=18428&action=view)
size of all object files using gcc 4.3


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41175

[Bug c/41175] New: -Os generates significantly larger code

[galak at kernel dot crashing dot org]

Using -Os with gcc4.4 vs gcc4.3 we see a ~15% increase in code size.  This is
due to the fact that load/store multiple instructions are not being used for
function prologue/epilogues.  The other option would be to use out of line
save/restore calls in the prologue/epilogues (which are also not being used).

We are no longer able to build the u-boot open source loader because the code
size increase expands beyond the allowable size (to meet flash constraints).


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           Summary: -Os generates significantly larger code
           Product: gcc
           Version: 4.4.1
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: galak at kernel dot crashing dot org
 GCC build triplet: ppc64-redhat-linux
  GCC host triplet: ppc64-redhat-linux
GCC target triplet: ppc64-redhat-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41175

[Bug c/41175] -Os generates significantly larger code

[galak at kernel dot crashing dot org]

------- Comment #2 from galak at kernel dot crashing dot org  2009-08-26 14:18 -------
Created an attachment (id=18429)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=18429&action=view)
size of all object files using gcc 4.4


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41175

[Bug c/41175] -Os generates significantly larger code

[galak at kernel dot crashing dot org]

------- Comment #3 from galak at kernel dot crashing dot org  2009-08-26 14:20 -------
I've attached comparisions of building the same u-boot source tree with gcc-4.3
from Fedora 10 on a PPC 64 host:

[galak@blarg u-boot-85xx]$ gcc -v
Using built-in specs.
Target: ppc64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
--infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla
--enable-bootstrap --enable-shared --enable-threads=posix
--enable-checking=release --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions
--enable-languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk
--disable-dssi --enable-plugin
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-1.5.0.0/jre
--enable-libgcj-multifile --enable-java-maintainer-mode
--with-ecj-jar=/usr/share/java/eclipse-ecj.jar --disable-libjava-multilib
--enable-secureplt --with-long-double-128 --build=ppc64-redhat-linux
--target=ppc64-redhat-linux --with-cpu=default32
Thread model: posix
gcc version 4.3.2 20081105 (Red Hat 4.3.2-7) (GCC) 

vs gcc 4.4 on a FC11 PPC64 host:

[root@ducky u-boot]# gcc -v
Using built-in specs.
Target: ppc64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
--infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla
--enable-bootstrap --enable-shared --enable-threads=posix
--enable-checking=release --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions
--enable-languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk
--disable-dssi --enable-plugin
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-1.5.0.0/jre
--enable-libgcj-multifile --enable-java-maintainer-mode
--with-ecj-jar=/usr/share/java/eclipse-ecj.jar --disable-libjava-multilib
--with-ppl --with-cloog --enable-secureplt --with-long-double-128
--build=ppc64-redhat-linux --target=ppc64-redhat-linux --with-cpu=default32
Thread model: posix
gcc version 4.4.1 20090725 (Red Hat 4.4.1-2) (GCC)


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41175

[Bug target/41175] -Os generates significantly larger code

[jakub at gcc dot gnu dot org]

------- Comment #4 from jakub at gcc dot gnu dot org  2009-09-10 23:11 -------
Created an attachment (id=18564)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=18564&action=view)
gcc45-pr41175.patch

Incremental fix on top of Nathan's patch.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41175

[Bug target/41175] -Os generates significantly larger code

[jakub at gcc dot gnu dot org]

------- Comment #5 from jakub at gcc dot gnu dot org  2009-09-15 20:12 -------
Subject: Bug 41175

Author: jakub
Date: Tue Sep 15 20:12:18 2009
New Revision: 151729

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=151729
Log:
        PR target/41175
        PR target/40677
        * config/rs6000/rs6000.c (no_global_regs_above): Fix precedence
        problem.
        (SAVRES_NOINLINE_GPRS_SAVES_LR, SAVRES_NOINLINE_FPRS_SAVES_LR,
        SAVRES_NOINLINE_FPRS_DOESNT_RESTORE_LR): New strategy bits.
        (rs6000_savres_strategy): Always save FP registers inline if the
        target doesn't support hardware double-precision.  Set the above
        bits in return value when needed.
        (rs6000_savres_routine_sym): Fix computation for cache selector.
        Mark the generated symbol as a function.  Rename exitp argument to
        lr.  Move code for determining the name of the symbol...
        (rs6000_savres_routine_name): ...here.  New function.  Add cases for
        getting the names right on AIX and 64-bit Linux.
        (savres_routine_name): New variable.
        (rs6000_make_savres_rtx): Rename exitp argument to lr.  Don't assert
        lr isn't set when savep.  Use r12 resp. r1 instead of r11 depending
        on what the target routine uses as a base register.  If savep && lr
        describe saving of r0 into memory slot.
        (rs6000_emit_prologue): Correct use of call_used_regs.  Fix out of
        line calls for AIX ABI.
        (rs6000_output_function_prologue): Use rs6000_savres_routine_name to
        determine FP save/restore functions.
        (rs6000_emit_stack_reset): Handle savres if sp_offset != 0 and
        frame_reg_rtx != sp_reg_rtx.  Use gen_add3_insn instead of
        gen_addsi3.
        (rs6000_emit_epilogue): Adjust computation of restore_lr.
        Duplicate restoration of LR and execute the appropriate one
        depending on whether GPRs are being restored inline.  Set r11 from
        offsetted frame_reg_rtx instead of sp_reg_rtx; if frame_reg_rtx is
        r11, adjust sp_offset.  Use gen_add3_insn instead of gen_addsi3.
        Fix out of line calls for AIX ABI.
        * config/rs6000/rs6000.md (*return_and_restore_fpregs_aix_<mode>):
        New insn.
        * config/rs6000/spe.md (*save_gpregs_spe): Use explicit match for
        register 11.
        (*restore_gpregs_spe): Likewise.
        (*return_and_restore_gpregs_spe): Likewise.
        * config/rs6000/linux64.h (SAVE_FP_SUFFIX, RESTORE_FP_SUFFIX):
        Define to empty string unconditionally.
        * config/rs6000/sysv4.h (SAVE_FP_SUFFIX, RESTORE_FP_SUFFIX):
        Define to empty string unconditionally.
        (GP_SAVE_INLINE, FP_SAVE_INLINE): Handle TARGET_64BIT the same as
        !TARGET_64BIT.

        * gcc.target/powerpc/pr41175.c: New test.

Added:
    trunk/gcc/testsuite/gcc.target/powerpc/pr41175.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/rs6000/linux64.h
    trunk/gcc/config/rs6000/rs6000.c
    trunk/gcc/config/rs6000/rs6000.md
    trunk/gcc/config/rs6000/spe.md
    trunk/gcc/config/rs6000/sysv4.h
    trunk/gcc/testsuite/ChangeLog


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41175

[Bug target/41175] -Os generates significantly larger code

[pinskia at gcc dot gnu dot org]

------- Comment #6 from pinskia at gcc dot gnu dot org  2009-10-05 22:22 -------
Fixed.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|major                       |normal
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41175