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8136615: aarch64: elide DecodeN when followed by CmpP 0

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Remove DecodeN when comparing a narrow oop with 0

Reviewed-by: kvn, adinn
This commit is contained in:
Ed Nevill 2015-09-16 13:50:57 +00:00
parent 92af9b015c
commit 050184d76f
1 changed files with 19 additions and 0 deletions
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19
hotspot/src/cpu/aarch64/vm/aarch64.ad
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@ -13814,6 +13814,25 @@ instruct cmpP_imm0_branch(cmpOp cmp, iRegP op1, immP0 op2, label labl, rFlagsReg
ins_pipe(pipe_cmp_branch);
%}
instruct cmpP_narrowOop_imm0_branch(cmpOp cmp, iRegN oop, immP0 zero, label labl, rFlagsReg cr) %{
match(If cmp (CmpP (DecodeN oop) zero));
predicate(n->in(1)->as_Bool()->_test._test == BoolTest::ne
|| n->in(1)->as_Bool()->_test._test == BoolTest::eq);
effect(USE labl);
ins_cost(BRANCH_COST);
format %{ "cb$cmp $oop, $labl" %}
ins_encode %{
Label* L = $labl$$label;
Assembler::Condition cond = (Assembler::Condition)$cmp$$cmpcode;
if (cond == Assembler::EQ)
__ cbzw($oop$$Register, *L);
else
__ cbnzw($oop$$Register, *L);
%}
ins_pipe(pipe_cmp_branch);
%}
// Conditional Far Branch
// Conditional Far Branch Unsigned
// TODO: fixme