78a46efff0
Introduce a fast path that avoids the `debug_tuple` abstraction when deriving Debug for unit-like enum variants. The intent here is to allow LLVM to remove the switch entirely in favor of an indexed load from a table of constant strings, which is likely what the programmer would write in C. Unfortunately, LLVM currently doesn't perform this optimization due to a bug, but there is [a patch](https://reviews.llvm.org/D109565) that fixes this issue. I've verified that, with that patch applied on top of this commit, Debug for unit-like tuple variants becomes a load, reducing the O(n) code bloat to O(1). Note that inlining `DebugTuple::finish()` wasn't enough to allow LLVM to optimize the code properly; I had to avoid the abstraction entirely. Not using the abstraction is likely better for compile time anyway. Part of #88793. r? `@oli-obk` |
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| .. | ||
| deriving | ||
| format_foreign | ||
| asm.rs | ||
| assert.rs | ||
| cfg_accessible.rs | ||
| cfg_eval.rs | ||
| cfg.rs | ||
| cmdline_attrs.rs | ||
| compile_error.rs | ||
| concat_idents.rs | ||
| concat.rs | ||
| derive.rs | ||
| env.rs | ||
| format_foreign.rs | ||
| format.rs | ||
| global_allocator.rs | ||
| lib.rs | ||
| llvm_asm.rs | ||
| log_syntax.rs | ||
| panic.rs | ||
| proc_macro_harness.rs | ||
| source_util.rs | ||
| standard_library_imports.rs | ||
| test_harness.rs | ||
| test.rs | ||
| trace_macros.rs | ||
| util.rs | ||