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8292867: RISC-V: Simplify weak CAS return value handling
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Reviewed-by: yadongwang, fyang
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@shipilev
shipilev committed Aug 25, 2022
1 parent 88af204 commit f57d342
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Showing 2 changed files with 26 additions and 37 deletions.
27 changes: 14 additions & 13 deletions src/hotspot/cpu/riscv/macroAssembler_riscv.cpp
View file
Expand Up @@ -2300,7 +2300,7 @@ void MacroAssembler::cmpxchg_narrow_value(Register addr, Register expected,
bnez(tmp, retry);

if (result_as_bool) {
addi(result, zr, 1);
li(result, 1);
j(done);

bind(fail);
Expand Down Expand Up @@ -2335,7 +2335,7 @@ void MacroAssembler::weak_cmpxchg_narrow_value(Register addr, Register expected,
assert_different_registers(addr, old, mask, not_mask, new_val, expected, shift, tmp);
cmpxchg_narrow_value_helper(addr, expected, new_val, size, tmp1, tmp2, tmp3);

Label succ, fail, done;
Label fail, done;

lr_w(old, aligned_addr, acquire);
andr(tmp, old, mask);
Expand All @@ -2344,13 +2344,14 @@ void MacroAssembler::weak_cmpxchg_narrow_value(Register addr, Register expected,
andr(tmp, old, not_mask);
orr(tmp, tmp, new_val);
sc_w(tmp, tmp, aligned_addr, release);
beqz(tmp, succ);
bnez(tmp, fail);

bind(fail);
addi(result, zr, 1);
// Success
li(result, 1);
j(done);

bind(succ);
// Fail
bind(fail);
mv(result, zr);

bind(done);
Expand Down Expand Up @@ -2394,20 +2395,20 @@ void MacroAssembler::cmpxchg_weak(Register addr, Register expected,
enum operand_size size,
Assembler::Aqrl acquire, Assembler::Aqrl release,
Register result) {
Label fail, done, sc_done;
Label fail, done;
load_reserved(addr, size, acquire);
bne(t0, expected, fail);
store_conditional(addr, new_val, size, release);
beqz(t0, sc_done);
bnez(t0, fail);

// fail
bind(fail);
// Success
li(result, 1);
j(done);

// sc_done
bind(sc_done);
mv(result, 0);
// Fail
bind(fail);
mv(result, zr);

bind(done);
}

Expand Down
36 changes: 12 additions & 24 deletions src/hotspot/cpu/riscv/riscv.ad
View file
Expand Up @@ -5650,14 +5650,13 @@ instruct weakCompareAndSwapB(iRegINoSp res, indirect mem, iRegI_R12 oldval, iReg

format %{
"cmpxchg_weak $mem, $oldval, $newval\t# (byte, weak) if $mem == $oldval then $mem <-- $newval\n\t"
"xori $res, $res, 1\t# $res == 1 when success, #@weakCompareAndSwapB"
"# $res == 1 when success, #@weakCompareAndSwapB"
%}

ins_encode %{
__ weak_cmpxchg_narrow_value(as_Register($mem$$base), $oldval$$Register, $newval$$Register, Assembler::int8,
/*acquire*/ Assembler::relaxed, /*release*/ Assembler::rl, $res$$Register,
$tmp1$$Register, $tmp2$$Register, $tmp3$$Register);
__ xori($res$$Register, $res$$Register, 1);
%}

ins_pipe(pipe_slow);
Expand All @@ -5674,14 +5673,13 @@ instruct weakCompareAndSwapS(iRegINoSp res, indirect mem, iRegI_R12 oldval, iReg

format %{
"cmpxchg_weak $mem, $oldval, $newval\t# (short, weak) if $mem == $oldval then $mem <-- $newval\n\t"
"xori $res, $res, 1\t# $res == 1 when success, #@weakCompareAndSwapS"
"# $res == 1 when success, #@weakCompareAndSwapS"
%}

ins_encode %{
__ weak_cmpxchg_narrow_value(as_Register($mem$$base), $oldval$$Register, $newval$$Register, Assembler::int16,
/*acquire*/ Assembler::relaxed, /*release*/ Assembler::rl, $res$$Register,
$tmp1$$Register, $tmp2$$Register, $tmp3$$Register);
__ xori($res$$Register, $res$$Register, 1);
%}

ins_pipe(pipe_slow);
Expand All @@ -5695,13 +5693,12 @@ instruct weakCompareAndSwapI(iRegINoSp res, indirect mem, iRegI oldval, iRegI ne

format %{
"cmpxchg_weak $mem, $oldval, $newval\t# (int, weak) if $mem == $oldval then $mem <-- $newval\n\t"
"xori $res, $res, 1\t# $res == 1 when success, #@weakCompareAndSwapI"
"# $res == 1 when success, #@weakCompareAndSwapI"
%}

ins_encode %{
__ cmpxchg_weak(as_Register($mem$$base), $oldval$$Register, $newval$$Register, Assembler::int32,
/*acquire*/ Assembler::relaxed, /*release*/ Assembler::rl, $res$$Register);
__ xori($res$$Register, $res$$Register, 1);
%}

ins_pipe(pipe_slow);
Expand All @@ -5715,13 +5712,12 @@ instruct weakCompareAndSwapL(iRegINoSp res, indirect mem, iRegL oldval, iRegL ne

format %{
"cmpxchg_weak $mem, $oldval, $newval\t# (long, weak) if $mem == $oldval then $mem <-- $newval\n\t"
"xori $res, $res, 1\t# $res == 1 when success, #@weakCompareAndSwapL"
"# $res == 1 when success, #@weakCompareAndSwapL"
%}

ins_encode %{
__ cmpxchg_weak(as_Register($mem$$base), $oldval$$Register, $newval$$Register, Assembler::int64,
/*acquire*/ Assembler::relaxed, /*release*/ Assembler::rl, $res$$Register);
__ xori($res$$Register, $res$$Register, 1);
%}

ins_pipe(pipe_slow);
Expand All @@ -5735,13 +5731,12 @@ instruct weakCompareAndSwapN(iRegINoSp res, indirect mem, iRegN oldval, iRegN ne

format %{
"cmpxchg_weak $mem, $oldval, $newval\t# (narrow oop, weak) if $mem == $oldval then $mem <-- $newval\n\t"
"xori $res, $res, 1\t# $res == 1 when success, #@weakCompareAndSwapN"
"# $res == 1 when success, #@weakCompareAndSwapN"
%}

ins_encode %{
__ cmpxchg_weak(as_Register($mem$$base), $oldval$$Register, $newval$$Register, Assembler::uint32,
/*acquire*/ Assembler::relaxed, /*release*/ Assembler::rl, $res$$Register);
__ xori($res$$Register, $res$$Register, 1);
%}

ins_pipe(pipe_slow);
Expand All @@ -5756,13 +5751,12 @@ instruct weakCompareAndSwapP(iRegINoSp res, indirect mem, iRegP oldval, iRegP ne

format %{
"cmpxchg_weak $mem, $oldval, $newval\t# (ptr, weak) if $mem == $oldval then $mem <-- $newval\n\t"
"xori $res, $res, 1\t# $res == 1 when success, #@weakCompareAndSwapP"
"# $res == 1 when success, #@weakCompareAndSwapP"
%}

ins_encode %{
__ cmpxchg_weak(as_Register($mem$$base), $oldval$$Register, $newval$$Register, Assembler::int64,
/*acquire*/ Assembler::relaxed, /*release*/ Assembler::rl, $res$$Register);
__ xori($res$$Register, $res$$Register, 1);
%}

ins_pipe(pipe_slow);
Expand All @@ -5781,14 +5775,13 @@ instruct weakCompareAndSwapBAcq(iRegINoSp res, indirect mem, iRegI_R12 oldval, i

format %{
"cmpxchg_weak_acq $mem, $oldval, $newval\t# (byte, weak) if $mem == $oldval then $mem <-- $newval\n\t"
"xori $res, $res, 1\t# $res == 1 when success, #@weakCompareAndSwapBAcq"
"# $res == 1 when success, #@weakCompareAndSwapBAcq"
%}

ins_encode %{
__ weak_cmpxchg_narrow_value(as_Register($mem$$base), $oldval$$Register, $newval$$Register, Assembler::int8,
/*acquire*/ Assembler::aq, /*release*/ Assembler::rl, $res$$Register,
$tmp1$$Register, $tmp2$$Register, $tmp3$$Register);
__ xori($res$$Register, $res$$Register, 1);
%}

ins_pipe(pipe_slow);
Expand All @@ -5807,14 +5800,13 @@ instruct weakCompareAndSwapSAcq(iRegINoSp res, indirect mem, iRegI_R12 oldval, i

format %{
"cmpxchg_weak_acq $mem, $oldval, $newval\t# (short, weak) if $mem == $oldval then $mem <-- $newval\n\t"
"xori $res, $res, 1\t# $res == 1 when success, #@weakCompareAndSwapSAcq"
"# $res == 1 when success, #@weakCompareAndSwapSAcq"
%}

ins_encode %{
__ weak_cmpxchg_narrow_value(as_Register($mem$$base), $oldval$$Register, $newval$$Register, Assembler::int16,
/*acquire*/ Assembler::aq, /*release*/ Assembler::rl, $res$$Register,
$tmp1$$Register, $tmp2$$Register, $tmp3$$Register);
__ xori($res$$Register, $res$$Register, 1);
%}

ins_pipe(pipe_slow);
Expand All @@ -5830,13 +5822,12 @@ instruct weakCompareAndSwapIAcq(iRegINoSp res, indirect mem, iRegI oldval, iRegI

format %{
"cmpxchg_weak_acq $mem, $oldval, $newval\t# (int, weak) if $mem == $oldval then $mem <-- $newval\n\t"
"xori $res, $res, 1\t# $res == 1 when success, #@weakCompareAndSwapIAcq"
"# $res == 1 when success, #@weakCompareAndSwapIAcq"
%}

ins_encode %{
__ cmpxchg_weak(as_Register($mem$$base), $oldval$$Register, $newval$$Register, Assembler::int32,
/*acquire*/ Assembler::aq, /*release*/ Assembler::rl, $res$$Register);
__ xori($res$$Register, $res$$Register, 1);
%}

ins_pipe(pipe_slow);
Expand All @@ -5852,13 +5843,12 @@ instruct weakCompareAndSwapLAcq(iRegINoSp res, indirect mem, iRegL oldval, iRegL

format %{
"cmpxchg_weak_acq $mem, $oldval, $newval\t# (long, weak) if $mem == $oldval then $mem <-- $newval\n\t"
"xori $res, $res, 1\t# $res == 1 when success, #@weakCompareAndSwapLAcq"
"# $res == 1 when success, #@weakCompareAndSwapLAcq"
%}

ins_encode %{
__ cmpxchg_weak(as_Register($mem$$base), $oldval$$Register, $newval$$Register, Assembler::int64,
/*acquire*/ Assembler::aq, /*release*/ Assembler::rl, $res$$Register);
__ xori($res$$Register, $res$$Register, 1);
%}

ins_pipe(pipe_slow);
Expand All @@ -5874,13 +5864,12 @@ instruct weakCompareAndSwapNAcq(iRegINoSp res, indirect mem, iRegN oldval, iRegN

format %{
"cmpxchg_weak_acq $mem, $oldval, $newval\t# (narrow oop, weak) if $mem == $oldval then $mem <-- $newval\n\t"
"xori $res, $res, 1\t# $res == 1 when success, #@weakCompareAndSwapNAcq"
"# $res == 1 when success, #@weakCompareAndSwapNAcq"
%}

ins_encode %{
__ cmpxchg_weak(as_Register($mem$$base), $oldval$$Register, $newval$$Register, Assembler::uint32,
/*acquire*/ Assembler::aq, /*release*/ Assembler::rl, $res$$Register);
__ xori($res$$Register, $res$$Register, 1);
%}

ins_pipe(pipe_slow);
Expand All @@ -5896,13 +5885,12 @@ instruct weakCompareAndSwapPAcq(iRegINoSp res, indirect mem, iRegP oldval, iRegP

format %{
"cmpxchg_weak_acq $mem, $oldval, $newval\t# (ptr, weak) if $mem == $oldval then $mem <-- $newval\n\t"
"xori $res, $res, 1\t# $res == 1 when success, #@weakCompareAndSwapPAcq"
"\t# $res == 1 when success, #@weakCompareAndSwapPAcq"
%}

ins_encode %{
__ cmpxchg_weak(as_Register($mem$$base), $oldval$$Register, $newval$$Register, Assembler::int64,
/*acquire*/ Assembler::aq, /*release*/ Assembler::rl, $res$$Register);
__ xori($res$$Register, $res$$Register, 1);
%}

ins_pipe(pipe_slow);
Expand Down

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