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: 24804k
    Peak memory use before GGC: 9642k
    Peak memory use after GGC: 8954k
    Maximum of released memory in single GGC run: 2790k
    Garbage: 42235k
    Leak: 6693k
    Overhead: 5844k
    GGC runs: 329

comparing combine.c compilation at -O1 level:
    Overall memory needed: 27616k -> 27596k
    Peak memory use before GGC: 9148k
    Peak memory use after GGC: 8709k
    Maximum of released memory in single GGC run: 2203k
    Garbage: 62901k -> 62894k
    Leak: 7074k
    Overhead: 7553k
    GGC runs: 522 -> 521

comparing combine.c compilation at -O2 level:
    Overall memory needed: 24800k
    Peak memory use before GGC: 18268k
    Peak memory use after GGC: 18081k
    Maximum of released memory in single GGC run: 2523k
    Garbage: 88065k -> 88049k
    Leak: 7039k
    Overhead: 10877k -> 10879k
    GGC runs: 483

comparing combine.c compilation at -O3 level:
  Amount of memory still referenced at the end of compilation increased from 7100k to 7128k, overall 0.39%
    Overall memory needed: 25068k -> 25100k
    Peak memory use before GGC: 18278k
    Peak memory use after GGC: 18081k
    Maximum of released memory in single GGC run: 3093k
    Garbage: 117440k -> 117442k
    Leak: 7100k -> 7128k
    Overhead: 14424k -> 14425k
    GGC runs: 538

comparing insn-attrtab.c compilation at -O0 level:
    Overall memory needed: 85588k
    Peak memory use before GGC: 73383k
    Peak memory use after GGC: 45353k
    Maximum of released memory in single GGC run: 37612k
    Garbage: 153233k
    Leak: 11531k
    Overhead: 19577k
    GGC runs: 268

comparing insn-attrtab.c compilation at -O1 level:
    Overall memory needed: 101096k
    Peak memory use before GGC: 76428k
    Peak memory use after GGC: 65583k
    Maximum of released memory in single GGC run: 37093k
    Garbage: 302935k -> 302927k
    Leak: 11592k
    Overhead: 36643k -> 36643k
    GGC runs: 382

comparing insn-attrtab.c compilation at -O2 level:
    Overall memory needed: 154168k -> 154120k
    Peak memory use before GGC: 118396k
    Peak memory use after GGC: 93014k
    Maximum of released memory in single GGC run: 32951k
    Garbage: 404102k -> 404098k
    Leak: 11434k
    Overhead: 49975k
    GGC runs: 306

comparing insn-attrtab.c compilation at -O3 level:
    Overall memory needed: 154156k -> 154172k
    Peak memory use before GGC: 118398k
    Peak memory use after GGC: 93016k
    Maximum of released memory in single GGC run: 32951k
    Garbage: 404890k -> 404887k
    Leak: 11455k
    Overhead: 50097k
    GGC runs: 312

comparing Gerald's testcase PR8361 compilation at -O0 level:
    Overall memory needed: 127316k
    Peak memory use before GGC: 103067k
    Peak memory use after GGC: 102045k
    Maximum of released memory in single GGC run: 21522k
    Garbage: 247319k
    Leak: 53785k
    Overhead: 42785k
    GGC runs: 346

comparing Gerald's testcase PR8361 compilation at -O1 level:
    Overall memory needed: 121424k
    Peak memory use before GGC: 112510k
    Peak memory use after GGC: 100687k
    Maximum of released memory in single GGC run: 20025k
    Garbage: 659417k -> 659385k
    Leak: 58897k
    Overhead: 83357k
    GGC runs: 517

comparing Gerald's testcase PR8361 compilation at -O2 level:
    Overall memory needed: 121404k
    Peak memory use before GGC: 112510k
    Peak memory use after GGC: 100687k
    Maximum of released memory in single GGC run: 20025k
    Garbage: 764740k -> 764681k
    Leak: 59593k -> 59585k
    Overhead: 102505k -> 102504k
    GGC runs: 610

comparing Gerald's testcase PR8361 compilation at -O3 level:
    Overall memory needed: 124356k
    Peak memory use before GGC: 115252k
    Peak memory use after GGC: 102513k
    Maximum of released memory in single GGC run: 21385k
    Garbage: 821248k -> 821207k
    Leak: 60842k
    Overhead: 108816k -> 108815k
    GGC runs: 609

Head of the ChangeLog is:

--- /usr/src/SpecTests/sandbox-britten-memory/x86_64/mem-result/ChangeLog	2005-05-29 22:11:12.000000000 +0000
+++ /usr/src/SpecTests/sandbox-britten-memory/gcc/gcc/ChangeLog	2005-05-30 05:41:25.000000000 +0000
@@ -1,3 +1,12 @@
+2005-05-30  Kazu Hirata  <kazu@cs.umass.edu>
+
+	* tree-outof-ssa.c (_elim_graph): Change the type of edge_list
+	to VEC(int,heap)*.
+	(new_elim_graph, clear_elim_graph, delete_elim_graph,
+	elim_graph_add_edge, elim_graph_remove_succ_edge,
+	FOR_EACH_ELIM_GRAPH_SUCC, FOR_EACH_ELIM_GRAPH_PRED): Use VEC
+	instead of VARRAY.
+
 2005-05-29  Kazu Hirata  <kazu@cs.umass.edu>
 
 	* cgraphunit.c, ipa-inline.c, loop-iv.c, modulo-sched.c,


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.