[Bug rtl-optimization/78325] New: [7 regression] r235825 causes gcc.target/mips/call-5.c, gcc.target/mips/call-6.c R_MIPS_JALR failures

[ma...@linux-mips.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78325

            Bug ID: 78325
           Summary: [7 regression] r235825 causes
                    gcc.target/mips/call-5.c, gcc.target/mips/call-6.c
                    R_MIPS_JALR failures
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ma...@linux-mips.org
  Target Milestone: ---
            Target: mips-linux-gnu

PR rtl-optimization/70890 fix (r235825) causes REG_EQUIV notes to be
removed from PIC call register loads in the MIPS new ABIs for function
calls to local symbols which use GOT_PAGE/GOT_OFST relocations.  These
notes are used in `mips_pic_call_symbol_from_set' to determine the
actual symbol referred in call insns and use it to produce a suitable
R_MIPS_JALR relocation.  Consequently the relocations are not output
anymore causing these regression test failures:

FAIL: gcc.target/mips/call-5.c   -O2   scan-assembler
\\.reloc\t1f,R_MIPS_JALR,staticfunc\n1:\tjalrc?\t
FAIL: gcc.target/mips/call-5.c   -O3 -g   scan-assembler
\\.reloc\t1f,R_MIPS_JALR,staticfunc\n1:\tjalrc?\t
FAIL: gcc.target/mips/call-5.c   -O2 -flto -fno-use-linker-plugin
-flto-partition=none   scan-assembler
\\.reloc\t1f,R_MIPS_JALR,staticfunc\n1:\tjalrc?\t
FAIL: gcc.target/mips/call-5.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects   scan-assembler
\\.reloc\t1f,R_MIPS_JALR,staticfunc\n1:\tjalrc?\t
FAIL: gcc.target/mips/call-6.c   -O2   scan-assembler
\\.reloc\t1f,R_MIPS_JALR,staticfunc\n1:\tjalrc?\t
FAIL: gcc.target/mips/call-6.c   -O3 -g   scan-assembler
\\.reloc\t1f,R_MIPS_JALR,staticfunc\n1:\tjalrc?\t
FAIL: gcc.target/mips/call-6.c   -O2 -flto -fno-use-linker-plugin
-flto-partition=none   scan-assembler
\\.reloc\t1f,R_MIPS_JALR,staticfunc\n1:\tjalrc?\t
FAIL: gcc.target/mips/call-6.c   -O2 -flto -fuse-linker-plugin
-fno-fat-lto-objects   scan-assembler
\\.reloc\t1f,R_MIPS_JALR,staticfunc\n1:\tjalrc?\t

and the linker cannot perform the branch optimisation intended, which
is especially relevant for function calls to local symbols.  With
r235825 reverted on top of current trunk these regressions are gone.