[Bug rtl-optimization/93088] New: [10 Regression] Compile time hog on gcc/testsuite/gcc.target/i386/pr56348.c w/ -O3 -funroll-loops -fno-tree-dominator-opts -fno-tree-vrp

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93088

            Bug ID: 93088
           Summary: [10 Regression] Compile time hog on
                    gcc/testsuite/gcc.target/i386/pr56348.c w/ -O3
                    -funroll-loops -fno-tree-dominator-opts -fno-tree-vrp
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Keywords: compile-time-hog
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---
            Target: x86_64-unknown-linux-gnu

gcc-10.0.0-alpha20191222 snapshot (r279712) takes inordinate time to compile
gcc/testsuite/gcc.target/i386/pr56348.c w/ -O3 -funroll-loops
-fno-tree-dominator-opts -fno-tree-vrp:

% timeout 30 x86_64-unknown-linux-gnu-gcc-10.0.0-alpha20191222 -O3
-funroll-loops -fno-tree-dominator-opts -fno-tree-vrp -c pr56348.c
zsh: exit 124   timeout 30 x86_64-unknown-linux-gnu-gcc-10.0.0-alpha20191222
-O3    -c

perf top shows only these two entries during the compilation:

Overhead  Sha  Symbol
  83.70%  cc1  [.] replace_single_def_regs
  16.30%  cc1  [.] find_reg_equal_equiv_note