[mlir][affine] Add AffineScope trait to scf.index_switch
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gptsarthak
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bondhugula
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| %3 = affine.load %1[%arg0] : memref<?xi1> | ||
| affine.store %3, %alloc[%arg0] : memref<?xi1> |
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Fixed. Thank you for reviewing my first patch in affine!
Do you think we can add this trait to scf.if and some other scf operations too? That will be very useful as it defines a new top level scope for symbols. Or we can just do that when an issue arises.
Adding the `AffineScope` trait to `scf.index_switch` solves llvm#64287. This defines a new top level scope for symbols, which proves highly practical as it enables a broader range of things to be represented as sequences of affine loop nests. I suggest that we add this trait to other SCF operations like `scf.for`, `scf.while` as well, as that will be very useful, and should not have any major issues that we cannot solve.
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Fixes #64287
The code in AffineStructures.cpp:FlatAffineValueConstraints' assert statement checks that the loop bound (i.e. val) isTopLevelValue or isForInductionVar. In this case,
%dim = memref.dim %20, %c0 : memref<?x?x6xi1>is neither, since it is insidescf.index_switch, which is not a part ofAffineScope. Thus, the assert is triggered.However,
%dim = memref.dim %20, %c0 : memref<?x?x6xi1>is an invariant in the scope of thescf.index_switch. If it was a loop, a invariant code motion could have hoisted it to be outside thescfscope, making it a validTopLevelValue.Adding the
AffineScopetrait toscf.index_switchsolves the issue. This defines a new top level scope for symbols, which proves highly practical as it enables a broader range of things to be represented as sequences of affine loop nests.I even suggest that we add this trait to other SCF operations like
scf.for,scf.whileas well, as that will be very useful, and should not have any major issues that we cannot solve.