Optimize C++ Backend for Conditional Fields #234
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Optimized the generated C++ code for structures with conditional fields
by identifying and caching repeated subexpressions (e.g., tag reads)
in the `Ok()`, `Equals()`, and `UncheckedEquals()` methods.
This approach uses a two-pass generation strategy:
1. Count usage of existence condition subexpressions.
2. Generate code where frequently used subexpressions are cached in
local variables at the method scope, while unique expressions are
inlined.
This reduces redundant computations (CPU optimization) without
introducing excessive stack usage for unique conditions (Memory
optimization).
Also updated test infrastructure to support passing compiler flags to
golden tests, fixing `no_enum_traits_golden_test`.
Added `testdata/many_conditionals.emb` and `compiler/back_end/cpp/testcode/many_conditionals_benchmark.cc`
to verify performance of conditional fields.
Performance Analysis (10,000 iterations x 100 tags on `testdata/many_conditionals.emb`):
- Baseline Runtime: ~1.83s
- Optimized Runtime: ~0.21s (Speedup: ~8.7x)
Binary Size Impact (many_conditionals_benchmark, -c opt):
- Baseline: 57848 bytes (text: 56112)
- Optimized: 30472 bytes (text: 28736) -> ~47% reduction
…aronWebster/emboss into copilot/fix-all-build-files-and-tests
Co-authored-by: AaronWebster <[email protected]>
…nd-tests Fix C++ backend conditional optimization: formatting and golden file regeneration
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This change significantly optimizes the generated C++ code for
structures utilizing conditional fields.
Key optimizations include:
frequently used subexpressions (e.g., tag reads) within Ok(),
Equals(), and UncheckedEquals() methods.
by a second pass that caches repeated expressions in local
variables while inlining unique ones.
performance improvements and reduced stack usage for unique
conditions.
Performance Impact (on testdata/many_conditionals.emb with 10,000
iterations x 100 tags):
bytes for many_conditionals_benchmark with -c opt).
Additional updates:
golden tests, resolving an issue with no_enum_traits_golden_test.
(compiler/back_end/cpp/testcode/many_conditionals_benchmark.cc)
were added to verify performance.