[tree-ssa] Miscompilation (SIGSEGV) with -ffast-math (!?), huge compile time regression

law@redhat.com law@redhat.com
Mon Feb 23 15:55:00 GMT 2004


In message <1077549687.3219.121.camel@localhost.localdomain>, Diego Novillo wri
tes:
 >On Mon, 2004-02-23 at 09:01, Richard Guenther wrote:
 >
 >> g++ (GCC) 3.5-tree-ssa 20040217 (merged 20040211) endlessly loops,
 >> g++ (GCC) 3.5-tree-ssa 20040209 (merged 20040126) is fine.  Note that 
 >> between these two a huge compile time regression occoured, 20040209 
 >> takes 6m36s, 20040217 over 12m!
 >> 
 >Yeah, it certainly takes a while to build (roughly 4m30s on a 2.2Ghz P4
 >w/ 1Gb of RAM).  It also makes cc1plus to grow quite big (about 480Mb).
 >
 >The biggest time consumers according to -ftime-report are
 >
 > dominator optimization:  47.83 (20%) usr   0.27 ( 4%) sys  48.29 (20%) wall
 > expand                :  46.79 (20%) usr   0.08 ( 1%) sys  46.95 (19%) wall
 > tree DSE              :  23.53 (10%) usr   0.01 ( 0%) sys  23.55 (10%) wall
 > tree SSA rewrite      :  16.31 ( 7%) usr   0.00 ( 0%) sys  16.31 ( 7%) wall
 > integration           :  13.86 ( 6%) usr   0.07 ( 1%) sys  13.93 ( 6%) wall
Care to pass along an oprofile function dump?  

jeff



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