[TypeProf][ICP]Tweak max number of vtables in cost-benefit analysis #105620
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…g vtable address point materialization cost
mingmingl-llvm
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mingmingl-llvm
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This tuning doesn't make a difference practically. Close this PR. |
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The ICP pass compares the vtable pointer with vtable address point for more efficient comparison sequence. The baseline is to compare the function pointer (loaded from vtable) with function address. The current cost-benefit analysis allows at most one vtable for each function candidate (to not insert instructions on hot paths).
icmp vtable-from-obj, getelementptr inbounds (i8, ptr @Derived2, i32 <constant-offset>)compares vtable loaded from object with a vtable address point offset. After lowering, its size cost depends on whethergetelementptr inbounds (i8, ptr @Derived2, i32 <constant-offset>can be folded into the icmp instruction.