Use the fact that in WGSL the scope corresponding to the loop construct
encloses the scope for its associated continue construct.
In our construct data structure, the two are adjacent but not
overlapping.
This improvement means that when a definition is in a loop construct,
but used only in the loop or associated continue construct, then no
hoisting is required.
Bug: tint:3
Change-Id: I8d33b8f76303ab2868306847e846b4c26899e746
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/24420
Reviewed-by: dan sinclair <dsinclair@google.com>
This also refactors break detection.
Bug: tint:3
Change-Id: I3a3e01c8d76d7c6fc2a14b3dbff136acd487e802
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/21220
Reviewed-by: dan sinclair <dsinclair@google.com>
Label basic blocks with:
- their nearest enclosing structured control flow constructs.
- their nearest enclosing continue construct, if any
- their nearest enclosing loop construct, if any
A construct consists of a span of blocks in the computed block order.
It knows its parent construct, if any, and its nesting depth.
Bug: tint:3
Change-Id: Ia945706e8ea2435d6c40fb4e36dc2daeeb9780d0
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/20421
Reviewed-by: dan sinclair <dsinclair@google.com>
