[PATCH] fwprop, updated patch and SPEC results

Paolo Bonzini paolo.bonzini@lu.unisi.ch
Sat Nov 4 17:30:00 GMT 2006


As reported on IRC, this is caused by the bitmaps for reaching 
definitions.  The increased peak consumption is because df allocates 
many bitmaps at the same time, more so than out-of-ssa or flow.c.  
fwprop is the first pass to use df for loopless testcases such as this one.

Bitmap                                     Overall Allocated     
Peak        Leak
---------------------------------------------------------------------------------
df-problems.c:986 (df_rd_alloc) 46040 259809052 259801720 0
df-problems.c:987 (df_rd_alloc) 46040 259827812 259816280 0

It may be worth taking a look at how the testcases behaves in dataflow 
branch.  (Just to recall, this is bug.c attached to PR28071, compiled 
with -O3 -fno-tree-pre -fno-tree-fre).  I'm using the bitmap statistics 
patch by Jan (available at 
http://gcc.gnu.org/ml/gcc-patches/2006-07/msg01244.html with 
s/bitmap_hash/bitmap_names_hash/g prior to applying it) to get the above 
data.

Paolo



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