http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45375
--- Comment #130 from Jan Hubicka <hubicka at gcc dot gnu.org> 2012-05-12 14:44:47 UTC --- After fixing one linker error, I can now build Mozilla with -flto-partition=none. It takes 11GB and 40 minutes, so there is space for improvement ;) There are some obvious questions, like why IRA needs 63% of GGC memory, and VRP 23% Also the -flto-partition=none .text section is now 18% smaller. This is large enough to be declared a bug, but I am not sure how to track it. Note that my macihne has quite poor since CPU performance, so the compile times are likely not comparable with LLVM ones reported above (and I also use debugging build). ipa lto gimple in : 52.12 ( 2%) usr 3.68 ( 9%) sys 55.72 ( 2%) wall 2998249 kB (84%) ggc ipa lto decl in : 225.68 ( 8%) usr 2.39 ( 6%) sys 228.17 ( 8%) wall 1124821 kB (31%) ggc ipa lto cgraph I/O : 4.82 ( 0%) usr 0.44 ( 1%) sys 5.27 ( 0%) wall 684110 kB (19%) ggc cfg construction : 3.01 ( 0%) usr 0.12 ( 0%) sys 3.29 ( 0%) wall 70205 kB ( 2%) ggc cfg cleanup : 46.57 ( 2%) usr 0.41 ( 1%) sys 46.69 ( 2%) wall 75005 kB ( 2%) ggc df live regs : 78.21 ( 3%) usr 0.25 ( 1%) sys 77.55 ( 3%) wall 0 kB ( 0%) ggc alias analysis : 25.59 ( 1%) usr 0.12 ( 0%) sys 25.88 ( 1%) wall 474769 kB (13%) ggc parser (global) : 8.62 ( 0%) usr 0.65 ( 2%) sys 10.00 ( 0%) wall 259389 kB ( 7%) ggc inline heuristics : 87.23 ( 3%) usr 0.51 ( 1%) sys 88.41 ( 3%) wall 451358 kB (13%) ggc integration : 50.61 ( 2%) usr 1.51 ( 4%) sys 52.67 ( 2%) wall 1479979 kB (41%) ggc tree CFG cleanup : 46.68 ( 2%) usr 0.43 ( 1%) sys 48.09 ( 2%) wall 70493 kB ( 2%) ggc tree VRP : 65.88 ( 2%) usr 0.73 ( 2%) sys 66.71 ( 2%) wall 862879 kB (24%) ggc tree copy propagation : 22.30 ( 1%) usr 0.17 ( 0%) sys 22.11 ( 1%) wall 144298 kB ( 4%) ggc tree PTA : 46.70 ( 2%) usr 0.06 ( 0%) sys 46.90 ( 2%) wall 100249 kB ( 3%) ggc tree SSA rewrite : 19.16 ( 1%) usr 0.15 ( 0%) sys 19.09 ( 1%) wall 149347 kB ( 4%) ggc tree SSA incremental : 27.75 ( 1%) usr 0.61 ( 1%) sys 27.86 ( 1%) wall 72307 kB ( 2%) ggc tree operand scan : 57.17 ( 2%) usr 3.03 ( 7%) sys 59.92 ( 2%) wall 1296208 kB (36%) ggc dominator optimization : 35.95 ( 1%) usr 0.21 ( 0%) sys 35.74 ( 1%) wall 311024 kB ( 9%) ggc tree CCP : 31.61 ( 1%) usr 0.12 ( 0%) sys 31.17 ( 1%) wall 111169 kB ( 3%) ggc tree PRE : 87.46 ( 3%) usr 0.60 ( 1%) sys 88.62 ( 3%) wall 538859 kB (15%) ggc tree FRE : 47.37 ( 2%) usr 0.58 ( 1%) sys 45.89 ( 2%) wall 274455 kB ( 8%) ggc tree aggressive DCE : 8.96 ( 0%) usr 0.22 ( 1%) sys 8.86 ( 0%) wall 137686 kB ( 4%) ggc tree forward propagate : 10.28 ( 0%) usr 0.10 ( 0%) sys 10.33 ( 0%) wall 56466 kB ( 2%) ggc tree slp vectorization : 25.42 ( 1%) usr 0.16 ( 0%) sys 25.50 ( 1%) wall 436119 kB (12%) ggc complete unrolling : 5.81 ( 0%) usr 0.13 ( 0%) sys 6.07 ( 0%) wall 115165 kB ( 3%) ggc tree vectorization : 1.44 ( 0%) usr 0.05 ( 0%) sys 1.36 ( 0%) wall 31337 kB ( 1%) ggc tree iv optimization : 13.00 ( 0%) usr 0.08 ( 0%) sys 12.94 ( 0%) wall 185893 kB ( 5%) ggc dominance computation : 48.61 ( 2%) usr 0.54 ( 1%) sys 47.65 ( 2%) wall 0 kB ( 0%) ggc expand vars : 18.81 ( 1%) usr 0.09 ( 0%) sys 18.42 ( 1%) wall 167798 kB ( 5%) ggc expand : 116.32 ( 4%) usr 0.61 ( 1%) sys 116.22 ( 4%) wall 1508612 kB (42%) ggc forward prop : 23.01 ( 1%) usr 0.36 ( 1%) sys 23.43 ( 1%) wall 130825 kB ( 4%) ggc CSE : 67.21 ( 2%) usr 0.23 ( 1%) sys 66.28 ( 2%) wall 44439 kB ( 1%) ggc dead store elim1 : 20.47 ( 1%) usr 0.10 ( 0%) sys 20.83 ( 1%) wall 103309 kB ( 3%) ggc dead store elim2 : 18.99 ( 1%) usr 0.18 ( 0%) sys 20.48 ( 1%) wall 140398 kB ( 4%) ggc CPROP : 52.83 ( 2%) usr 0.33 ( 1%) sys 52.91 ( 2%) wall 336514 kB ( 9%) ggc PRE : 30.60 ( 1%) usr 0.06 ( 0%) sys 30.51 ( 1%) wall 52724 kB ( 1%) ggc CSE 2 : 37.89 ( 1%) usr 0.04 ( 0%) sys 38.88 ( 1%) wall 29785 kB ( 1%) ggc combiner : 80.20 ( 3%) usr 0.23 ( 1%) sys 80.57 ( 3%) wall 400168 kB (11%) ggc integrated RA : 191.13 ( 7%) usr 0.44 ( 1%) sys 190.64 ( 7%) wall 2328880 kB (65%) ggc reload : 65.46 ( 2%) usr 0.09 ( 0%) sys 67.43 ( 2%) wall 193522 kB ( 5%) ggc reload CSE regs : 56.71 ( 2%) usr 0.14 ( 0%) sys 56.49 ( 2%) wall 241394 kB ( 7%) ggc thread pro- & epilogue : 14.43 ( 1%) usr 0.15 ( 0%) sys 14.97 ( 1%) wall 201098 kB ( 6%) ggc final : 44.77 ( 2%) usr 2.80 ( 6%) sys 48.99 ( 2%) wall 367580 kB (10%) ggc rest of compilation : 57.58 ( 2%) usr 6.23 (14%) sys 63.50 ( 2%) wall 337908 kB ( 9%) ggc remove unused locals : 41.68 ( 2%) usr 0.15 ( 0%) sys 42.04 ( 1%) wall 333 kB ( 0%) ggc TOTAL :2768.94 43.11 2814.85 3588723 kB