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[Qemu-devel] [PATCH 0/7] Double-word tcg/optimize improvements
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH 0/7] Double-word tcg/optimize improvements |
Date: |
Thu, 27 Sep 2012 10:19:50 -0700 |
In another thread we talked about doing the brcond2 -> brcond optimization
generically for LT/GTE comparisons vs zero. That's patch 4 of this series.
In addition, it seemed trivial to go ahead and apply the existing code we
have for fully optimizing constant comparisons.
Tested host i686, guest alpha. Where even the final patch activates during
the boot rom. (FYI, implver is sorta like cpuid, querying cpu revision.)
0xfffffc0000003748: implver t0
0xfffffc000000374c: cmpeq t0,0x1,t1
0xfffffc0000003750: bne t1,0x40000003784
OP:
---- 0xfffffc0000003748
movi_i32 ir1_0,$0x2
movi_i32 ir1_1,$0x0
---- 0xfffffc000000374c
movi_i32 tmp0,$0x1
movi_i32 tmp1,$0x0
setcond2_i32 ir2_0,ir1_0,ir1_1,tmp0,tmp1,eq
movi_i32 ir2_1,$0x0
---- 0xfffffc0000003750
mov_i32 tmp0,ir2_0
mov_i32 tmp1,ir2_1
movi_i32 tmp2,$0x0
movi_i32 tmp3,$0x0
brcond2_i32 tmp0,tmp1,tmp2,tmp3,ne,$0x0
...
OP after optimization and liveness analysis:
---- 0xfffffc0000003748
movi_i32 ir1_0,$0x2
movi_i32 ir1_1,$0x0
---- 0xfffffc000000374c
nopn $0x2,$0x2
nopn $0x2,$0x2
movi_i32 ir2_0,$0x0
movi_i32 ir2_1,$0x0
---- 0xfffffc0000003750
nopn $0x2,$0x2
nopn $0x2,$0x2
nopn $0x2,$0x2
nopn $0x2,$0x2
nop
...
r~
Richard Henderson (7):
tcg: Split out swap_commutative as a subroutine
tcg: Optimize add2 + sub2
tcg: Swap commutative double-word comparisons
tcg: Optimize double-word comparisons against zero
tcg: Split out subroutines from do_constant_folding_cond
tcg: Tidy brcond optimization
tcg: Do constant folding on double-word comparisons
tcg/optimize.c | 366 +++++++++++++++++++++++++++++++++++++++++----------------
1 file changed, 267 insertions(+), 99 deletions(-)
--
1.7.11.4
- [Qemu-devel] [PATCH 0/7] Double-word tcg/optimize improvements,
Richard Henderson <=
- [Qemu-devel] [PATCH 1/7] tcg: Split out swap_commutative as a subroutine, Richard Henderson, 2012/09/27
- [Qemu-devel] [PATCH 2/7] tcg: Optimize add2 + sub2, Richard Henderson, 2012/09/27
- [Qemu-devel] [PATCH 4/7] tcg: Optimize double-word comparisons against zero, Richard Henderson, 2012/09/27
- [Qemu-devel] [PATCH 7/7] tcg: Do constant folding on double-word comparisons, Richard Henderson, 2012/09/27
- [Qemu-devel] [PATCH 6/7] tcg: Tidy brcond optimization, Richard Henderson, 2012/09/27
- [Qemu-devel] [PATCH 3/7] tcg: Swap commutative double-word comparisons, Richard Henderson, 2012/09/27