------- Comment #22 from jakub at gcc dot gnu dot org 2007-11-01 20:59 ------- The most important cause of the slowdown e.g. compared to 4.2.x is the totally insane thing -ftree-pre creates though. For -O3 -fno-tree-vectorize -fdump-tree-all pr33922.c wc -l shows 2361 pr33922.c.090t.sink while for -O3 -fno-tree-vectorize -fno-tree-pre -fdump-tree-all pr33922.c 324 pr33922.c.090t.sink and of course the size of assembly corresponds to this: 11400 pr33922.s # -O3 -fno-tree-vectorize 195 pr33922.s # -O3 -fno-tree-vectorize -fno-tree-pre
-O3 -fno-tree-vectorize -fdump-tree-pre-all dump contains 2081 ^Created.*value lines and all those constants are actually created and many PHI nodes as well. I believe this might be what nickc was trying to fix today by adding a limit, but wasn't that limit huge (131072 bits)? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33922
