[Bug bootstrap/93398] PGO bootstrap is not reproducible

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93398

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|WORKSFORME                  |---
             Status|RESOLVED                    |REOPENED

--- Comment #10 from Martin Liška <marxin at gcc dot gnu.org> ---
It's so easy to end up with a different binary for GCC:

@@ -174,7 +174,7 @@
 .//objdir/gcc/c/c-decl.gcda:    01ab0000:   0:COUNTERS average 0 counts
 .//objdir/gcc/c/c-decl.gcda:    01ad0000:   0:COUNTERS ior 0 counts
 .//objdir/gcc/c/c-decl.gcda:    01af0000:   2:COUNTERS time_profiler 1 counts
-.//objdir/gcc/c/c-decl.gcda:                   0: 2419 
+.//objdir/gcc/c/c-decl.gcda:                   0: 2420 
 .//objdir/gcc/c/c-decl.gcda:  01000000:   3:FUNCTION ident=1446792123,
lineno_checksum=0x069e6627, cfg_checksum=0x4c361918
 .//objdir/gcc/c/c-decl.gcda:    01a10000:  28:COUNTERS arcs 14 counts
 .//objdir/gcc/c/c-decl.gcda:                   0: 29954 2 2 28793 0 0 873 0 
@@ -184,7 +184,7 @@
 .//objdir/gcc/c/c-decl.gcda:    01ab0000:   0:COUNTERS average 0 counts
 .//objdir/gcc/c/c-decl.gcda:    01ad0000:   0:COUNTERS ior 0 counts
 .//objdir/gcc/c/c-decl.gcda:    01af0000:   2:COUNTERS time_profiler 1 counts
-.//objdir/gcc/c/c-decl.gcda:                   0: 2421 
+.//objdir/gcc/c/c-decl.gcda:                   0: 2422 
 .//objdir/gcc/c/c-decl.gcda:  01000000:   3:FUNCTION ident=1033776594,
lineno_checksum=0x0314bcea, cfg_checksum=0xa707611a
 .//objdir/gcc/c/c-decl.gcda:    01a10000:  16:COUNTERS arcs 8 counts
 .//objdir/gcc/c/c-decl.gcda:                   0: 50 16 0 50 0 50 0 0 

So a slightly different tp_first_run can cause different function order:

$ objfolderdiff.py
/home/marxin/BIG/buildbot/buildworker/marxinbox-gcc-reproducible/base/objdir/gcc/
/home/marxin/BIG/buildbot/buildworker/marxinbox-gcc-reproducible/next/objdir/gcc/
-d
   103/   624: c/c-decl.o: different
---
/home/marxin/BIG/buildbot/buildworker/marxinbox-gcc-reproducible/base/objdir/gcc/c/c-decl.o.s.txt
  2020-04-07 17:43:18.280993473 +0200
+++
/home/marxin/BIG/buildbot/buildworker/marxinbox-gcc-reproducible/next/objdir/gcc/c/c-decl.o.s.txt
  2020-04-07 17:43:18.280993473 +0200
@@ -34570,15 +34570,6 @@
   36:  89 f8                   mov    %edi,%eax
   38:  c3                      retq   

-Disassembly of section .text._Z17ggc_cleared_allocI9lang_typeEPT_v:
-
-0000000000000000 <_Z17ggc_cleared_allocI9lang_typeEPT_v>:
-   0:  b9 01 00 00 00          mov    $0x1,%ecx
-   5:  31 d2                   xor    %edx,%edx
-   7:  31 f6                   xor    %esi,%esi
-   9:  bf 20 00 00 00          mov    $0x20,%edi
-   e:  e9 00 00 00 00          jmpq   13 <current_function_returns_null+0x3>
-
 Disassembly of section .text.hot._Z15hash_table_mod2jj:

 0000000000000000 <_Z15hash_table_mod2jj>:
@@ -34618,6 +34609,15 @@
 }
   3c:  c3                      retq   

+Disassembly of section .text._Z17ggc_cleared_allocI9lang_typeEPT_v:
+
+0000000000000000 <_Z17ggc_cleared_allocI9lang_typeEPT_v>:
+   0:  b9 01 00 00 00          mov    $0x1,%ecx
+   5:  31 d2                   xor    %edx,%edx
+   7:  31 f6                   xor    %esi,%esi
+   9:  bf 20 00 00 00          mov    $0x20,%edi
+   e:  e9 00 00 00 00          jmpq   13 <current_function_returns_null+0x3>
+
 Disassembly of section
.text.hot._ZN2wi5neg_pI16generic_wide_intI20wide_int_ref_storageILb1ELb0EEEEEbRKT_6signop:

 0000000000000000
<_ZN2wi5neg_pI16generic_wide_intI20wide_int_ref_storageILb1ELb0EEEEEbRKT_6signop>: