A recent patch increased GCC's memory consumption!

[gcctest@suse.de]

Hi,

I am a friendly script caring about memory consumption in GCC.  Please
contact jh@suse.cz if something is going wrong.

Comparing memory consumption on compilation of combine.i, insn-attrtab.i,
and generate-3.4.ii I got:


comparing combine.c compilation at -O0 level:
    Overall memory needed: 25056k
    Peak memory use before GGC: 9509k
    Peak memory use after GGC: 8897k
    Maximum of released memory in single GGC run: 2602k
    Garbage: 38652k -> 38655k
    Leak: 6733k
    Overhead: 5889k
    GGC runs: 303 -> 304

comparing combine.c compilation at -O1 level:
    Overall memory needed: 26892k
    Peak memory use before GGC: 17430k
    Peak memory use after GGC: 17251k
    Maximum of released memory in single GGC run: 2284k
    Garbage: 59422k -> 59420k
    Leak: 6882k
    Overhead: 7046k -> 7046k
    GGC runs: 377

comparing combine.c compilation at -O2 level:
    Overall memory needed: 26892k
    Peak memory use before GGC: 17435k
    Peak memory use after GGC: 17251k
    Maximum of released memory in single GGC run: 2387k
    Garbage: 83218k -> 83216k
    Leak: 6996k
    Overhead: 9690k -> 9690k
    GGC runs: 442

comparing combine.c compilation at -O3 level:
    Overall memory needed: 25992k
    Peak memory use before GGC: 18537k
    Peak memory use after GGC: 17840k
    Maximum of released memory in single GGC run: 3516k
    Garbage: 113347k -> 113345k
    Leak: 7086k
    Overhead: 13186k -> 13186k
    GGC runs: 494

comparing insn-attrtab.c compilation at -O0 level:
  Amount of memory still referenced at the end of compilation increased from 9885k to 9901k, overall 0.16%
    Overall memory needed: 82164k
    Peak memory use before GGC: 69036k
    Peak memory use after GGC: 44790k
    Maximum of released memory in single GGC run: 36009k
    Garbage: 140382k -> 140381k
    Leak: 9885k -> 9901k
    Overhead: 20394k -> 20394k
    GGC runs: 239

comparing insn-attrtab.c compilation at -O1 level:
    Overall memory needed: 105340k
    Peak memory use before GGC: 85347k
    Peak memory use after GGC: 79195k
    Maximum of released memory in single GGC run: 32286k
    Garbage: 283067k -> 283065k
    Leak: 10065k
    Overhead: 33382k -> 33382k
    GGC runs: 239

comparing insn-attrtab.c compilation at -O2 level:
    Overall memory needed: 107912k -> 107916k
    Peak memory use before GGC: 89760k
    Peak memory use after GGC: 81649k
    Maximum of released memory in single GGC run: 30736k
    Garbage: 330591k -> 330590k
    Leak: 10051k
    Overhead: 40625k -> 40625k
    GGC runs: 264

comparing insn-attrtab.c compilation at -O3 level:
    Overall memory needed: 107928k
    Peak memory use before GGC: 89786k
    Peak memory use after GGC: 81675k
    Maximum of released memory in single GGC run: 30934k
    Garbage: 331201k -> 331200k
    Leak: 10056k
    Overhead: 40821k -> 40821k
    GGC runs: 268

comparing Gerald's testcase PR8361 compilation at -O0 level:
    Overall memory needed: 118260k
    Peak memory use before GGC: 95032k -> 95031k
    Peak memory use after GGC: 94083k
    Maximum of released memory in single GGC run: 20360k -> 20359k
    Garbage: 218496k -> 218411k
    Leak: 49513k
    Overhead: 37972k -> 37967k
    GGC runs: 363

comparing Gerald's testcase PR8361 compilation at -O1 level:
    Overall memory needed: 115852k -> 115856k
    Peak memory use before GGC: 97679k
    Peak memory use after GGC: 96699k
    Maximum of released memory in single GGC run: 18987k
    Garbage: 463624k -> 463615k
    Leak: 52800k
    Overhead: 51424k -> 51424k
    GGC runs: 509

comparing Gerald's testcase PR8361 compilation at -O2 level:
    Overall memory needed: 115848k
    Peak memory use before GGC: 97679k
    Peak memory use after GGC: 96700k
    Maximum of released memory in single GGC run: 18987k
    Garbage: 552446k -> 552437k
    Leak: 53701k
    Overhead: 60154k -> 60154k
    GGC runs: 589

comparing Gerald's testcase PR8361 compilation at -O3 level:
    Overall memory needed: 117132k
    Peak memory use before GGC: 98973k
    Peak memory use after GGC: 97993k
    Maximum of released memory in single GGC run: 19240k
    Garbage: 572423k -> 572416k
    Leak: 54058k
    Overhead: 61151k -> 61151k
    GGC runs: 599

Head of the ChangeLog is:

--- /usr/src/SpecTests/sandbox-britten-memory/x86_64/mem-result/ChangeLog	2006-04-18 11:24:22.000000000 +0000
+++ /usr/src/SpecTests/sandbox-britten-memory/gcc/gcc/ChangeLog	2006-04-18 13:03:41.000000000 +0000
@@ -1,3 +1,11 @@
+2006-04-18  Kazu Hirata  <kazu@codesourcery.com>
+
+	* function.c (temp_slots_at_level, max_slot_level): Use VEC
+	instead of VARRAY.
+	* function.h (temp_slot_p): New.
+	(function): Change the type of x_used_temp_slots to
+	VEC(temp_slot_p,gc) *.
+
 2006-04-18  Nick Clifton  <nickc@redhat.com>
 
 	* config/mmix/mmix.h (OPTIMIZATION_OPTIONS): Remove reference to


The results can be reproduced by building a compiler with

--enable-gather-detailed-mem-stats targetting x86-64

and compiling preprocessed combine.c or testcase from PR8632 with:

-fmem-report --param=ggc-min-heapsize=1024 --param=ggc-min-expand=1 -Ox -Q

The memory consumption summary appears in the dump after detailed listing
of the places they are allocated in.  Peak memory consumption is actually
computed by looking for maximal value in {GC XXXX -> YYYY} report.

Your testing script.