Hello. I've got a patch candidate that leverages partial linking for a couple of selected object files.
I'm sending make all-host- jX results for my machine: before: 3m18s (user 32m52s) https://gist.githubusercontent.com/marxin/223890df4d8d8e490b6b2918b77dacad/raw/1dd5eae5001295ba0230a689f7edc67284c9b742/gcc-all-host.svg after: 2m57m (user 35m) https://gist.githubusercontent.com/marxin/223890df4d8d8e490b6b2918b77dacad/raw/d659b2187cf622167841efbbe6bc93cb33855fa9/gcc-all-host-partial-lto.svg One can utilize it with: make -j16 all-host PARTIAL_LTO=1 @Segher, Andrew: Can you please measure time improvement for your slow bootstrap? One can also tweak --param=lto-partitions=16 param value. Thoughts? Thanks, Martin
>From 85228e612610c0e4b0324f6bebc84ef7c0211c4a Mon Sep 17 00:00:00 2001 From: Martin Liska <mli...@suse.cz> Date: Thu, 20 May 2021 14:29:35 +0200 Subject: [PATCH] Try LTO partial linking. --- gcc/Makefile.in | 30 ++++++++++++++++++++++++++---- 1 file changed, 26 insertions(+), 4 deletions(-) diff --git a/gcc/Makefile.in b/gcc/Makefile.in index 1164554e6d6..f76bcea66f5 100644 --- a/gcc/Makefile.in +++ b/gcc/Makefile.in @@ -220,7 +220,9 @@ libgcov-util.o-warn = -Wno-error libgcov-driver-tool.o-warn = -Wno-error libgcov-merge-tool.o-warn = -Wno-error gimple-match.o-warn = -Wno-unused +gimple-match-lto.o-warn = -Wno-unused generic-match.o-warn = -Wno-unused +generic-match-lto.o-warn = -Wno-unused dfp.o-warn = -Wno-strict-aliasing # All warnings have to be shut off in stage1 if the compiler used then @@ -1282,12 +1284,10 @@ ANALYZER_OBJS = \ # will build them sooner, because they are large and otherwise tend to be # the last objects to finish building. OBJS = \ - gimple-match.o \ - generic-match.o \ + common-base.a \ insn-attrtab.o \ insn-automata.o \ insn-dfatab.o \ - insn-emit.o \ insn-extract.o \ insn-latencytab.o \ insn-modes.o \ @@ -1295,7 +1295,6 @@ OBJS = \ insn-output.o \ insn-peep.o \ insn-preds.o \ - insn-recog.o \ insn-enums.o \ ggc-page.o \ adjust-alignment.o \ @@ -2627,6 +2626,29 @@ s-match: build/genmatch$(build_exeext) $(srcdir)/match.pd cfn-operators.pd generic-match.c $(STAMP) s-match +ifdef PARTIAL_LTO +LTO_LINKER_FLAGS = -flto=auto --param=lto-partitions=16 -flinker-output=nolto-rel -r +LTO_FLAGS = -flto + +gimple-match-lto.o: gimple-match.c $(TARGET_H) + $(COMPILE) $< $(LTO_FLAGS) +generic-match-lto.o: generic-match.c $(TARGET_H) + $(COMPILE) $< $(LTO_FLAGS) +insn-recog-lto.o: insn-recog.c + $(COMPILE) $< $(LTO_FLAGS) +insn-emit-lto.o: insn-emit.c + $(COMPILE) $< $(LTO_FLAGS) + +common-base.a: gimple-match-lto.o generic-match-lto.o insn-recog-lto.o insn-emit-lto.o + -rm -rf $@ + $(LINKER) $^ $(LTO_LINKER_FLAGS) -o common-base.o + $(AR) $(AR_FLAGS)T $@ common-base.o +else +common-base.a: gimple-match.o generic-match.o insn-recog.o insn-emit.o + -rm -rf $@ + $(AR) $(AR_FLAGS)T $@ $^ +endif + GTFILES = $(CPPLIB_H) $(srcdir)/input.h $(srcdir)/coretypes.h \ $(host_xm_file_list) \ $(tm_file_list) $(HASHTAB_H) $(SPLAY_TREE_H) $(srcdir)/bitmap.h \ -- 2.31.1
