tcg: optimize across branches

[PATCH 0/2] tcg: optimize across branches

Richard Henderson posted 2 patches 3 years, 7 months ago

Download series mbox

Test checkpatch passed

Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/20201013222330.173525-1-richard.henderson@linaro.org

Maintainers: Richard Henderson <rth@twiddle.net>

include/tcg/tcg-opc.h |  7 +++---
include/tcg/tcg.h     |  4 +++-
tcg/optimize.c        | 35 ++++++++++++++-------------
tcg/tcg.c             | 55 +++++++++++++++++++++++++++++++++++++++++--
4 files changed, 78 insertions(+), 23 deletions(-)

Expand all Fold all

[PATCH 0/2] tcg: optimize across branches

Posted by Richard Henderson 3 years, 7 months ago

In several cases, it's easy to optimize across a non-taken branch
simply by *not* flushing the relevant tables.  This is true both
for value propagation and register allocation.

This comes up in quite a number of cases with arm, most simply in
how conditional execution is implemented.  But it also came up in
discussion of how to implement low-overhead looping for v8.1m.


r~


Richard Henderson (2):
  tcg: Do not kill globals at conditional branches
  tcg/optimize: Flush data at labels not TCG_OPF_BB_END

 include/tcg/tcg-opc.h |  7 +++---
 include/tcg/tcg.h     |  4 +++-
 tcg/optimize.c        | 35 ++++++++++++++-------------
 tcg/tcg.c             | 55 +++++++++++++++++++++++++++++++++++++++++--
 4 files changed, 78 insertions(+), 23 deletions(-)

-- 
2.25.1

Re: [PATCH 0/2] tcg: optimize across branches

Posted by Richard Henderson 3 years, 6 months ago

Ping.

On 10/13/20 3:23 PM, Richard Henderson wrote:
> In several cases, it's easy to optimize across a non-taken branch
> simply by *not* flushing the relevant tables.  This is true both
> for value propagation and register allocation.
> 
> This comes up in quite a number of cases with arm, most simply in
> how conditional execution is implemented.  But it also came up in
> discussion of how to implement low-overhead looping for v8.1m.
> 
> 
> r~
> 
> 
> Richard Henderson (2):
>   tcg: Do not kill globals at conditional branches
>   tcg/optimize: Flush data at labels not TCG_OPF_BB_END
> 
>  include/tcg/tcg-opc.h |  7 +++---
>  include/tcg/tcg.h     |  4 +++-
>  tcg/optimize.c        | 35 ++++++++++++++-------------
>  tcg/tcg.c             | 55 +++++++++++++++++++++++++++++++++++++++++--
>  4 files changed, 78 insertions(+), 23 deletions(-)
>