Backport for rust#127286 and rust#127260 #175
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Expose the memory addressing to simplify checking stack spill/restore manipulation codegen (cherry picked from commit 8270485)
…(x),c)) if the pattern has multiple uses Fixes llvm#97533 crash where we hit a case where the root node had referenced the original zext node, which we then deleted - hopefully I can come up with a better solution, but the codegen changes don't look too bad atm (pulls out a shift from some complex LEA nodes that shared the scaled index). (cherry picked from commit e975ff0)
For llvm#97702. (cherry picked from commit e7bfd4d)
…value (llvm#97711) If there is a single store, then loads must either load the stored value or uninitialized memory (undef). If the stored value may be poison, then replacing an uninitialized memory load with it would be incorrect. Fall back to the generic code in that case. This PR only fixes the case where there is a literal poison store -- the case where the value is non-trivially poison will still get miscompiled by phi simplification later, see llvm#96631. Fixes llvm#97702. (cherry picked from commit f58930f)
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Please hold this for now. |
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llvm@daaea12 addresses a compile-time regression from the mem2reg change. |
In llvm#97711 the single-store optimization was disabled for the case where the value is potentially poison, as this may produce incorrect results for loads of uninitialized memory. However, this resulted in compile-time regressions. Address these by still allowing the single-store optimization to occur in cases where the store dominates the load, as we know that such a load will always read initialized memory. (cherry picked from commit daaea12)
Added. The new changes also look easier to understand. |
nikic
approved these changes
Jul 5, 2024
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Fixes rust-lang/rust#127286 and rust-lang/rust#127260.
Backport llvm#97711 and llvm#97533.
The fileThe test case is inllvm/test/CodeGen/X86/var-permute-128.llcontains conflicts, so I regenerated this test. Strangely, the test doesn't seem to have changed?llvm/test/CodeGen/X86/addr-mode-matcher-3.ll.