The LTO branch has been merged into trunk at revision 152434. Please note that trunk remains CLOSED. I would like to give automatic testers a chance to pick up the merge and test it in isolation. I plan to open trunk in 48 hours (Mon 5 Oct).
Following this message, I will post the final 13 patches, roughly split by directories. Instructions on how to enable LTO support are described in the manual. The following is a summary: - Install libelf 0.8.12+ (http://www.mr511.de/software/libelf-0.8.12.tar.gz) Other versions of libelf are commonly installed in Linux distros. Unfortunately, libelf implementations vary in annoying ways and they are not all compatible. The libelf version in Fedora 11 works fine, however. - Configure and build with $ mkdir bld && cd bld $ ../trunk/configure --with-libelf=<path-to-libelf> $ make If libelf is installed in a system path, you don't need to specify --with-libelf, of course. To enable LTO, simply add the flag '-flto' to both compile and link commands. It doesn't really matter whether you compile and link in separate invocations or a single one. All that matters is that -flto should be in both places: $ gcc -flto -O2 -o f f1.c f2.c or $ gcc -flto -c f1.c $ gcc -flto -c f2.c $ gcc -o f -flto -O2 f1.o f2.o That's it. The result should, in principle, execute faster but our IPA cost models are still not tweaked for LTO. We've seen speedups as well as slowdowns in benchmarks (see the LTO testers at http://gcc.opensuse.org/). Please report performance and correctness issues in Bugzilla. I bootstrapped and tested the merge on x86_64-unknown-linux-gnu, i686-pc-linux-gnu and powerpc64-unknown-linux-gnu. Additionally the merge has been bootstrapped and tested on these targets (http://gcc.gnu.org/ml/gcc/2009-09/msg00566.html): alphaev68-unknown-linux-gnu i386-pc-solaris2.10 i586-suse-linux-gnu i686-pc-linux-gnu ia64-suse-linux-gnu mipsisa64-unknown-elf powerpc64-suse-linux-gnu powerpc64-unknown-linux-gnu s390-ibm-linux-gnu s390x-ibm-linux-gnu sh4-unknown-linux-gnu x86_64-suse-linux-gnu x86_64-unknown-linux-gnu sparc-sun-solaris2.11 Richi bootstrapped and tested on {i586,x86_64,ppc,ppc64,ia64,s390,s390x}-linux-gnu with LTO disabled. Thanks to all the folks who contributed cycles for this! You should expect the following LTO-related failures, which will be fixed during stage 3. From what I've seen, I believe that most of these failures are already in bugzilla. I've summarized the LTO-related failures below, if there is anything missing please report it in bugzilla. Particularly those that seem target-specific. --------------------------------------------------------------------------- Common to most targets: FAIL: g++.dg/lto/20090106 cp_lto_20090106_0.o-cp_lto_20090106_0.o link FAIL: g++.dg/lto/20090311 cp_lto_20090311_0.o-cp_lto_20090311_1.o link FAIL: gcc.c-torture/execute/builtins/sprintf-chk.c execution FAIL: gcc.c-torture/execute/builtins/stpcpy-chk.c execution FAIL: gcc.c-torture/execute/builtins/strcpy-chk.c execution FAIL: gfortran.dg/lto/pr40725 f_lto_pr40725_0.o-f_lto_pr40725_1.o execute -O2 -flto FAIL: gfortran.dg/lto/pr40725 f_lto_pr40725_0.o-f_lto_pr40725_1.o execute -O2 -fwhopr --------------------------------------------------------------------------- Common to some targets: i386-pc-solaris2.10 i686-pc-linux-gnu i586-suse-linux-gnu mipsisa64-elf powerpc64-suse-linux-gnu sh4-unknown-linux-gnu FAIL: g++.dg/lto/20081109 cp_lto_20081109_0.o-cp_lto_20081109_1.o execute -O0 -fwhopr FAIL: g++.dg/lto/20081109 cp_lto_20081109_0.o-cp_lto_20081109_1.o execute -O2 -fwhopr i386-pc-solaris2.10 mipsisa64-elf sparc-sun-solaris2.11 FAIL: g++.dg/lto/20081120-1 cp_lto_20081120-1_0.o-cp_lto_20081120-1_1.o link FAIL: g++.dg/lto/20081120-2 cp_lto_20081120-2_0.o-cp_lto_20081120-2_1.o link i586-suse-linux-gnu ia64-suse-linux-gnu s390-ibm-linux-gnu sh4-unknown-linux-gnu FAIL: gcc.dg/torture/builtin-math-7.c -O2 -flto (internal compiler error) FAIL: gcc.dg/torture/builtin-math-7.c -O2 -flto (test for excess errors) FAIL: gcc.dg/torture/builtin-math-7.c -O2 -fwhopr (internal compiler error) FAIL: gcc.dg/torture/builtin-math-7.c -O2 -fwhopr (test for excess errors) mipsisa64-elf sh4-unknown-linux-gnu FAIL: gcc.dg/lto/20081112 c_lto_20081112_0.o-c_lto_20081112_1.o link FAIL: gcc.dg/lto/20081118 c_lto_20081118_0.o-c_lto_20081118_2.o link --------------------------------------------------------------------------- Individual target failures: i386-pc-solaris2.10 FAIL: g++.dg/lto/20080908-3 cp_lto_20080908-3_0.o-cp_lto_20080908-3_0.o execute -O0 -flto FAIL: g++.dg/lto/20080908-3 cp_lto_20080908-3_0.o-cp_lto_20080908-3_0.o execute -O0 -fwhopr FAIL: gcc.dg/lto/20081126 c_lto_20081126_0.o-c_lto_20081126_0.o link FAIL: gcc.dg/lto/20090126-1 c_lto_20090126-1_0.o-c_lto_20090126-1_0.o link FAIL: gcc.dg/lto/20090126-2 c_lto_20090126-2_0.o-c_lto_20090126-2_0.o link FAIL: gcc.dg/lto/20090729 c_lto_20090729_0.o-c_lto_20090729_1.o link ia64-suse-linux-gnu FAIL: g++.dg/lto/20081217-1 cp_lto_20081217-1_0.o-cp_lto_20081217-1_0.o link FAIL: g++.dg/lto/20081217-2 cp_lto_20081217-2_0.o-cp_lto_20081217-2_0.o link FAIL: gcc.c-torture/execute/vector-2.c execution, -O2 -flto FAIL: gcc.c-torture/execute/vector-2.c execution, -O2 -fwhopr mipsisa64-elf FAIL: g++.dg/lto/20081119-1 cp_lto_20081119-1_0.o-cp_lto_20081119-1_1.o link FAIL: g++.dg/lto/20081123 cp_lto_20081123_0.o-cp_lto_20081123_1.o link FAIL: g++.dg/lto/20081204-1 cp_lto_20081204-1_0.o-cp_lto_20081204-1_1.o link FAIL: g++.dg/lto/20081219 cp_lto_20081219_0.o-cp_lto_20081219_1.o link FAIL: g++.dg/lto/20090302 cp_lto_20090302_0.o-cp_lto_20090302_1.o link FAIL: g++.dg/lto/20090313 cp_lto_20090313_0.o-cp_lto_20090313_1.o link FAIL: gcc.dg/lto/20081204-1 c_lto_20081204-1_0.o-c_lto_20081204-1_1.o link FAIL: gcc.dg/lto/20081212-1 c_lto_20081212-1_0.o-c_lto_20081212-1_0.o link powerpc64-suse-linux-gnu FAIL: gcc.c-torture/execute/20071030-1.c execution, -O2 -flto FAIL: gcc.c-torture/execute/20071030-1.c execution, -O2 -fwhopr FAIL: gcc.dg/vmx/* -O2 {-fwhopr,-flto} sparc-sun-solaris2.11 FAIL: gcc.dg/lto/20081120-1 c_lto_20081120-1_0.o-c_lto_20081120-1_1.o link FAIL: gcc.dg/lto/20081201-2 c_lto_20081201-2_0.o-c_lto_20081201-2_1.o FAIL: gcc.dg/lto/20090729 c_lto_20090729_0.o-c_lto_20090729_1.o link FAIL: tmpdir-g++.dg-struct-layout-1/t003 cp_compat_x_tst.o-cp_compat_y_tst.o execute "-O2","-flto" FAIL: tmpdir-g++.dg-struct-layout-1/t003 cp_compat_x_tst.o-cp_compat_y_tst.o execute "-O2","-fwhopr" FAIL: tmpdir-g++.dg-struct-layout-1/t019 cp_compat_x_tst.o-cp_compat_y_tst.o execute "-O2","-flto" FAIL: tmpdir-g++.dg-struct-layout-1/t019 cp_compat_x_tst.o-cp_compat_y_tst.o execute "-O2","-fwhopr" FAIL: tmpdir-g++.dg-struct-layout-1/t030 cp_compat_x_tst.o-cp_compat_y_tst.o execute "-O2","-flto" FAIL: tmpdir-g++.dg-struct-layout-1/t030 cp_compat_x_tst.o-cp_compat_y_tst.o execute "-O2","-fwhopr" sh4-unknown-linux-gnu FAIL: gcc.dg/lto/20090218 c_lto_20090218_0.o-c_lto_20090218_3.o link FAIL: gcc.dg/lto/20090218-2 c_lto_20090218-2_0.o-c_lto_20090218-2_1.o link FAIL: gfortran.dg/lto/pr40724 f_lto_pr40724_0.o-f_lto_pr40724_1.o link
