[Bug c++/87436] [7/8/9 Regression] G++ produces >300MB .rodata section to initialize struct with big array

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87436

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 45230
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45230&action=edit
gcc9-pr87436.patch

The following patch addresses the memory consumption and to some extent compile
time issue, but doesn't change what is emitted.

Unpatched trunk:
Time variable                                   usr           sys          wall
              GGC
 phase setup                        :   0.00 (  0%)   0.00 (  0%)   0.01 (  0%)
   1355 kB (  0%)
 phase parsing                      :   0.01 (  0%)   0.00 (  0%)   0.00 (  0%)
    638 kB (  0%)
 phase opt and generate             : 506.62 (100%)   2.20 (100%) 510.10
(100%)39325772 kB (100%)
 garbage collection                 :   4.84 (  1%)   0.47 ( 21%)   5.36 (  1%)
      0 kB (  0%)
 callgraph construction             :   0.01 (  0%)   0.00 (  0%)   0.00 (  0%)
      5 kB (  0%)
 ipa dead code removal              :   0.01 (  0%)   0.00 (  0%)   0.01 (  0%)
      0 kB (  0%)
 ipa icf                            :   2.06 (  0%)   0.00 (  0%)   2.06 (  0%)
      0 kB (  0%)
 parser (global)                    :   0.01 (  0%)   0.00 (  0%)   0.00 (  0%)
    571 kB (  0%)
 integration                        :  28.56 (  6%)   0.00 (  0%)  28.63 (  6%)
2621665 kB (  7%)
 tree gimplify                      :   7.33 (  1%)   1.24 ( 56%)   8.58 (  2%)
5244044 kB ( 13%)
 tree VRP                           :   0.01 (  0%)   0.00 (  0%)   0.01 (  0%)
      2 kB (  0%)
 tree Early VRP                     :  63.00 ( 12%)   0.00 (  0%)  63.16 ( 12%)
5243330 kB ( 13%)
 tree PTA                           :   0.01 (  0%)   0.00 (  0%)   0.01 (  0%)
      0 kB (  0%)
 tree CCP                           :  33.00 (  7%)   0.00 (  0%)  33.09 (  6%)
2621664 kB (  7%)
 tree PRE                           :  43.59 (  9%)   0.00 (  0%)  43.70 (  9%)
2621665 kB (  7%)
 tree FRE                           :  92.77 ( 18%)   0.00 (  0%)  93.02 ( 18%)
7864992 kB ( 20%)
 tree forward propagate             : 200.09 ( 39%)   0.01 (  0%) 200.62 (
39%)13108320 kB ( 33%)
 tree conservative DCE              :   0.02 (  0%)   0.00 (  0%)   0.01 (  0%)
      0 kB (  0%)
 tree loop optimization             :   0.00 (  0%)   0.00 (  0%)   0.01 (  0%)
      0 kB (  0%)
 expand                             :   1.80 (  0%)   0.00 (  0%)   1.80 (  0%)
      5 kB (  0%)
 integrated RA                      :   0.09 (  0%)   0.00 (  0%)   0.10 (  0%)
     24 kB (  0%)
 final                              :  29.41 (  6%)   0.47 ( 21%)  29.92 (  6%)
      1 kB (  0%)
 rest of compilation                :   0.02 (  0%)   0.01 (  0%)   0.01 (  0%)
      2 kB (  0%)
 TOTAL                              : 506.63          2.20        510.11      
39327775 kB

Patched trunk:
Time variable                                   usr           sys          wall
              GGC
 phase setup                        :   0.00 (  0%)   0.14 ( 15%)   0.14 (  0%)
   1355 kB ( 64%)
 phase opt and generate             :  27.58 (100%)   0.49 ( 53%)  28.11 ( 92%)
    112 kB (  5%)
 phase finalize                     :   0.01 (  0%)   0.29 ( 32%)   2.26 (  7%)
      0 kB (  0%)
 final                              :  27.57 (100%)   0.49 ( 53%)  28.10 ( 92%)
      1 kB (  0%)
 initialize rtl                     :   0.01 (  0%)   0.00 (  0%)   0.01 (  0%)
     12 kB (  1%)
 TOTAL                              :  27.59          0.92         30.51       
   2116 kB