[LLHD] Allow projections across blocks in mem2reg #8855
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The Mem2Reg pass currently refuses to promote projections that have uses in different blocks. This is an unnecessary limitation, since the fact that a projection dominates a drive means that any operands of the projection, e.g. an array index, also dominate the drive. Therefore the drive can still be replaced with extract/inject operations using the projection operands. This only starts to become a problem once we allow projections to be passed as branch destination operands, which we do not. Remove this unnecessary check, since it prevents some real-world use cases from being properly handled by mem2reg.
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The Mem2Reg pass currently refuses to promote projections that have uses in different blocks. This is an unnecessary limitation, since the fact that a projection dominates a drive means that any operands of the projection, e.g. an array index, also dominate the drive. Therefore the drive can still be replaced with extract/inject operations using the projection operands. This only starts to become a problem once we allow projections to be passed as branch destination operands, which we do not.
Remove this unnecessary check, since it prevents some real-world use cases from being properly handled by mem2reg.