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From: "jakub at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/43632] [4.5 Regression] -g option became very slow after r157834 Date: Tue, 06 Apr 2010 10:08:00 -0000 [thread overview] Message-ID: <20100406100743.4555.qmail@sourceware.org> (raw) In-Reply-To: <bug-43632-17259@http.gcc.gnu.org/bugzilla/> ------- Comment #5 from jakub at gcc dot gnu dot org 2010-04-06 10:07 ------- callgrind --inclusive=yes says on this: 438,822,838,411 /usr/src/gcc/obj/gcc/../../gcc/var-tracking.c:variable_tracking_main 429,638,024,208 /usr/src/gcc/obj/libiberty/../../libiberty/hashtab.c:htab_traverse_noresize [/usr/src/gcc/obj/gcc/cc1plus] 428,305,658,767 /usr/src/gcc/obj/libiberty/../../libiberty/hashtab.c:htab_traverse [/usr/src/gcc/obj/gcc/cc1plus] 417,506,443,433 ../../gcc/var-tracking.c:vt_find_locations [/usr/src/gcc/obj/gcc/cc1plus] 389,486,317,740 ../../gcc/var-tracking.c:dataflow_set_merge [/usr/src/gcc/obj/gcc/cc1plus] 389,242,104,098 /usr/src/gcc/obj/gcc/../../gcc/var-tracking.c:variable_merge_over_cur 389,242,104,098 ../../gcc/var-tracking.c:variable_merge_over_cur [/usr/src/gcc/obj/gcc/cc1plus] 345,572,722,020 ../../gcc/var-tracking.c:intersect_loc_chains [/usr/src/gcc/obj/gcc/cc1plus] 292,844,158,243 ../../gcc/var-tracking.c:find_loc_in_1pdv [/usr/src/gcc/obj/gcc/cc1plus] 117,800,020,698 /usr/src/gcc/obj/gcc/../../gcc/rtl.c:rtx_equal_p 117,800,020,698 ../../gcc/rtl.c:rtx_equal_p [/usr/src/gcc/obj/gcc/cc1plus] 78,786,470,332 /usr/src/gcc/obj/libiberty/../../libiberty/hashtab.c:htab_find_with_hash [/usr/src/gcc/obj/gcc/cc1plus] so, as a micro-optimization what could work is use the spare bits in location_chain_def (30 bits on 32-bit hosts, 32 + 30 bits on 64-bit hosts) for something we could compare quickly in place of rtx_equal_p resp. loc_cmp. Say, having two or 3 topmost bits of those 30 for code (0 for REG, 1 for MEM, 2 for VALUE, 3 for anything else) and for each code encode something in the other bits (e.g. REGNO for REG, 2 bits REG/MEM/VALUE/other for MEM's address than the rest of bits, saturating VALUE uid for VALUEs, something else for other codes). Then we'd call rtx_equal_p or loc_cmp only if two values are equal. Or better find a way how to do less work during dataflow merges. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43632
next prev parent reply other threads:[~2010-04-06 10:08 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-04-02 19:38 [Bug c++/43632] New: " roman at binarylife dot net 2010-04-02 19:42 ` [Bug c++/43632] " roman at binarylife dot net 2010-04-02 20:25 ` jakub at gcc dot gnu dot org 2010-04-02 20:26 ` [Bug rtl-optimization/43632] [4.5 Regression] " rguenth at gcc dot gnu dot org 2010-04-02 21:04 ` ebotcazou at gcc dot gnu dot org 2010-04-03 17:18 ` rguenth at gcc dot gnu dot org 2010-04-06 10:08 ` jakub at gcc dot gnu dot org [this message] 2010-04-06 11:28 ` rguenth at gcc dot gnu dot org 2010-06-04 19:34 ` [Bug rtl-optimization/43632] [4.5/4.6 " jakub at gcc dot gnu dot org
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