[llvm] [mlir] [MLGO] Do not hardcode 33 eviction feature columns (PR #224598)

[Arseniy Obolenskiy via llvm-commits]

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@@ -24,7 +24,8 @@
 ]
 """
 PER_REGISTER_FEATURE_LIST = ["mask"]
-NUM_REGISTERS = 33
+# Must match getRequiredNumColumns() for the target the tests run on (X86).
+NUM_REGISTERS = 37
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aobolensk wrote:

Reverted back to 33. I don't really understand the 33 number, getNumAllocatableRegs returns 16 and I see even now the most of the numbers are 0s. For now I left it max(32, actual_reg_count) which seem not to regress the x86 case here. But 33 is odd

https://github.com/llvm/llvm-project/pull/224598