sv.c: sv_2mortal() move SvTEMP_on(sv); for RISC CPUs #23427
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RISC CPUs can not read from memory and do anything else in 1 opcode. These x64 instructions are impossible to do in 1 opcode on ARM. F7 42 0C 00 00 01 08 test dword ptr [rdx+0Ch], 8010000h and 0F BA 6B 0C 13 bts dword ptr [rbx+0Ch], 13h Since editing macro SvIMMORTAL() to remove SvREADONLY() is out of scope, flip the order around, so the contents sv->sv_flags can be reused, and not re-read around fn call Perl_tmps_grow_p(). sv_2mortal() is a libperl export, it doesn't inline. "SvTEMP_on(sv);" can not have any CC inline synergy/de-duping opportunities with its caller frame, regardless if SvTEMP_on() is on the top or bottom of sv_2mortal(). sv.c itself never calls sv_2mortal(). All functions inside sv.c use the lightweight PUSH_EXTEND_MORTAL__SV_C() macro, not sv_2mortal().
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RISC CPUs can not read from memory and do anything else in 1 opcode. These x64 instructions are impossible to do in 1 opcode on ARM.
F7 42 0C 00 00 01 08 test dword ptr [rdx+0Ch], 8010000h
and
0F BA 6B 0C 13 bts dword ptr [rbx+0Ch], 13h
Since editing macro SvIMMORTAL() to remove SvREADONLY() is out of scope, flip the order around, so the contents sv->sv_flags can be reused, and not re-read around fn call Perl_tmps_grow_p().
sv_2mortal() is a libperl export, it doesn't inline. "SvTEMP_on(sv);" can not have any CC inline synergy/de-duping opportunities with its caller frame, regardless if SvTEMP_on() is on the top or bottom of sv_2mortal(). sv.c itself never calls sv_2mortal(). All functions inside sv.c use the lightweight PUSH_EXTEND_MORTAL__SV_C() macro, not sv_2mortal().