When we determine that a function only contains a single return
statement and it is at the top level (i.e. not inside any scopes),
there is no need to create a temporary variable and store the
result expression into a variable. Instead, we can directly replace
the function-call expression with the return-statement's expression.
Unlike my previous solution, this does not require variable
declarations to be rewritten. The no-scopes limitation makes it
slightly less effective in theory, but in practice we still get
almost all of the benefit. The no-scope limitation bites us on
structures like
@if (true) {
return x;
} else {
return y;
}
Which will optimize away the if, but leave the scope:
{
return x;
}
However, this is not a big deal; the biggest wins are single-line
helper functions like `guarded_divide` and `unpremul` which retain
the full benefit.
Change-Id: I7fbb725e65db021b9795c04c816819669815578f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/345167
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
This reverts commit 345d72124d.
Reason for revert: can break ES2 for-loop rules
Original change's description:
> Eliminate inliner temporary variables for functions with a single exit.
>
> When we determine that a function only contains a single return
> statement, there is no need to create a temporary variable and store the
> result expression into a variable. Instead, we can directly replace the
> function-call expression with the return-statement's expression.
>
> This dramatically simplifies the final optimized output from chains of
> very simple inlined functions, which is a very common pattern for trees
> of Skia fragment processors.
>
> Change-Id: I6789064a321daf43db2e1cef4915f25ed74d6131
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/344665
> Commit-Queue: John Stiles <johnstiles@google.com>
> Reviewed-by: Brian Osman <brianosman@google.com>
> Auto-Submit: John Stiles <johnstiles@google.com>
TBR=brianosman@google.com,ethannicholas@google.com,johnstiles@google.com
Change-Id: I60845f22159605a06047b030e2686a769121a35a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/345120
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
When we determine that a function only contains a single return
statement, there is no need to create a temporary variable and store the
result expression into a variable. Instead, we can directly replace the
function-call expression with the return-statement's expression.
This dramatically simplifies the final optimized output from chains of
very simple inlined functions, which is a very common pattern for trees
of Skia fragment processors.
Change-Id: I6789064a321daf43db2e1cef4915f25ed74d6131
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/344665
Commit-Queue: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
We now have SPIR-V golden outputs for `blend` and `shared` tests.
This exposes a handful of SPIR-V limitations for us to address.
Change-Id: Ie5278889b8a61432403d06231b17765885bee0ac
Bug: skia:10694
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/337182
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
