[Bug target/88343] [7/8/9 Regression] R31 is unconditionally saved/restored on powerpc-darwin even when it's not necessary.

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88343

Iain Sandoe <iains at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|powerpc-darwin              |powerpc-darwin,
                   |                            |powerpc-linux-gnu

--- Comment #3 from Iain Sandoe <iains at gcc dot gnu.org> ---
actually, m32 powerpc-linux-gnu seems affected too.

The only change that the commit causing this introduced was makrking the
picbase as non-copyable.

-----

$ echo "void foo (void) {} " | ./gcc/xgcc -Bgcc -x c - -S -o t.s -O2 -fPIC
-fomit-frame-pointer -m32

$ more t.s
        .file   ""
        .machine power4
        .section        ".text"
        .align 2
        .p2align 4,,15
        .globl foo
        .type   foo, @function
foo:
.LFB0:
        .cfi_startproc
        stwu 1,-16(1)
        .cfi_def_cfa_offset 16
        stw 30,8(1)
        .cfi_offset 30, -8
        ori 2,2,0
        lwz 30,8(1)
        addi 1,1,16
        .cfi_restore 30
        .cfi_def_cfa_offset 0
        blr
        .cfi_endproc
.LFE0:
        .size   foo,.-foo
        .ident  "GCC: (GNU) 9.0.0 20181203 (experimental) [trunk revision
266733]"
        .section        .note.GNU-stack,"",@progbits