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[0/2] tcg: optimize across branches

Message ID 20201013222330.173525-1-richard.henderson@linaro.org
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Series tcg: optimize across branches | expand

Message

Richard Henderson Oct. 13, 2020, 10:23 p.m. UTC 
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(-)

Comments

Richard Henderson Oct. 19, 2020, 11:04 p.m. UTC | #1 
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(-)
>