`FAKE_USE`s are essentially no-ops, so they have to be removed before running ExplicitLocals so that `drop`s will be correctly inserted to drop those values used by the `FAKE_USE`s. --- This is reapplication of #160228, which broke Wasm waterfall. This PR additionally prevents `FAKE_USE`s uses from being stackified. Previously, a 'def' whose first use was a `FAKE_USE` was able to be stackified as `TEE`: - Before ``` Reg = INST ... // Def FAKE_USE ..., Reg, ... // Insert INST ..., Reg, ... INST ..., Reg, ... ``` - After RegStackify ``` DefReg = INST ... // Def TeeReg, Reg = TEE ... DefReg FAKE_USE ..., TeeReg, ... // Insert INST ..., Reg, ... INST ..., Reg, ... ``` And this assumes `DefReg` and `TeeReg` are stackified. But this PR removes `FAKE_USE`s in the beginning of ExplicitLocals. And later in ExplicitLocals we have a routine to unstackify registers that have no uses left: https://github.com/llvm/llvm-project/blob/7b28fcd2b182ba2c9d2d71c386be92fc0ee3cc9d/llvm/lib/Target/WebAssembly/WebAssemblyExplicitLocals.cpp#L257-L269 (This was added in #149626. Then it didn't seem it would trigger the same assertions for `TEE`s because it was fixing the bug where a terminator was removed in CFGSort (#149097). Details here: https://github.com/llvm/llvm-project/pull/149432#issuecomment-3091444141) - After `FAKE_USE` removal and unstackification ``` DefReg = INST ... TeeReg, Reg = TEE ... DefReg INST ..., Reg, ... INST ..., Reg, ... ``` And now `TeeReg` is unstackified. This triggered the assertion here, that `TeeReg` should be stackified: https://github.com/llvm/llvm-project/blob/7b28fcd2b182ba2c9d2d71c386be92fc0ee3cc9d/llvm/lib/Target/WebAssembly/WebAssemblyExplicitLocals.cpp#L316 This prevents `FAKE_USE`s' uses from being stackified altogether, including `TEE` transformation. Even when it is not a `TEE` transformation and just a single use stackification, it does not trigger the assertion but there's no point stackifying it given that it will be deleted. --- Fixes https://github.com/emscripten-core/emscripten/issues/25301.
Reverts llvm/llvm-project#160228 See https://github.com/llvm/llvm-project/pull/160228#issuecomment-3329752471
`FAKE_USE`s are essentially no-ops, so they have to be removed before running ExplicitLocals so that `drop`s will be correctly inserted to drop those values used by the `FAKE_USE`s. Fixes https://github.com/emscripten-core/emscripten/issues/25301.
There are cases we end up removing some intructions that use stackified registers after RegStackify. For example, ```wasm bb.0: %0 = ... ;; %0 is stackified br_if %bb.1, %0 bb.1: ``` In this code, br_if will be removed in CFGSort, so we should unstackify %0 so that it can be correctly dropped in ExplicitLocals. Rather than handling this in case-by-case basis, this PR just unstackifies all stackifies register with no uses in the beginning of ExplicitLocals, so that they can be correctly dropped. Fixes #149097.
Use the nonstatic member instead. I'm pretty sure the code in SPRIV is a layering violation. MC layer files are using a CodeGen header.
These are the the ones where we already had a Register object being used. Some places are still using unsigned which I did not convert.
- Add `MachineBlockFrequencyAnalysis`. - Add `MachineBlockFrequencyPrinterPass`. - Use `MachineBlockFrequencyInfoWrapperPass` in legacy pass manager. - `LazyMachineBlockFrequencyInfo::print` is empty, drop it due to new pass manager migration.
This adds (back) the exnref type restored in the new EH proposal adopted in Oct 2023 CG meeting: https://github.com/WebAssembly/exception-handling/blob/main/proposals/exception-handling/Exceptions.md:x
Move WebAssemblyUtilities from Utils to the CodeGen library. It primarily deals in MIR layer types, so it really lives in the CodeGen library. Move a variety of other things around to try create better separation. See issue #64166 for more info on layering. Move llvm/include/CodeGen/WasmAddressSpaces.h back to llvm/lib/Target/WebAssembly/Utils. Differential Revision: https://reviews.llvm.org/D156472
We have a good comment on `TEE` transformation in `RegStackify`: https://github.com/llvm/llvm-project/blob/547e3456660000a16fc5c2a2f819f1a2b5d35b5d/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp#L613-L632 And I think it can be helpful to have some more comments on how the `TEE`s created in `RegStackify` are converted into `LOCAL_TEE`s. Variable `OldReg` is changed to `DefReg` to be consistent with `RegStackify`'s comment. Reviewed By: tlively Differential Revision: https://reviews.llvm.org/D146084