[TIR] Fix reverse_compute_at for trivial region with trivial block var

[vinx13]

This PR fixed compute_at / reverse_compute_at when block access regions contain constants (e.g. A[0, vi, vj]).
Background:
#11187 added additional simplification when creating prim func from TE. This may result in block var with constant binding values simplified.

cc @junrushao1994 @spectrometerHBH @zxybazh @shingjan

[shingjan]

LGTM. Can confirm that this PR fixed my repro on meta_schedule with LLVM. Thanks! @vinx13. BTW do you have any insight on why this issue is only happening on LLVM but not CUDA?

[vinx13]

CUDA will call cache_write to introduce a cache block first, so the block used for reverse_compute_at is different, and the bindings we are dealing with might also be different

[zxybazh]

LGTM. Thanks for the quick fix and thanks to @shingjan for reporting this issue!

[junrushao]

Reading the cryptic error message, it seems that the IntervalSet sometimes is used to represent handle vs int, so it cans CanProveEqual - a bit weird to me, but definitely fixable with more guards

  16: _M_invoke
        at /usr/include/c++/7/bits/std_function.h:316
  15: operator()
        at /workspace/src/te/operation/compute_op.cc:216
  14: tvm::arith::IntSetAnalyzer::operator()(tvm::PrimExpr const&, tvm::runtime::Map<tvm::tir::Var, tvm::arith::IntSet, void, void> const&)
        at /workspace/src/arith/int_set.cc:521
  13: tvm::arith::IntSetAnalyzer::Impl::Eval(tvm::PrimExpr const&, tvm::runtime::Map<tvm::tir::Var, tvm::arith::IntSet, void, void> const&) const
        at /workspace/src/arith/int_set.cc:509
  12: tvm::arith::IntervalSetEvaluator::Eval(tvm::PrimExpr const&)
        at /workspace/src/arith/int_set.cc:351
  11: tvm::tir::ExprFunctor<tvm::arith::IntervalSet (tvm::PrimExpr const&)>::VisitExpr(tvm::PrimExpr const&)
        at /workspace/include/tvm/tir/expr_functor.h:114
  10: tvm::NodeFunctor<tvm::arith::IntervalSet (tvm::runtime::ObjectRef const&, tvm::tir::ExprFunctor<tvm::arith::IntervalSet (tvm::PrimExpr const&)>*)>::operator()(tvm::runtime::ObjectRef const&, tvm::tir::ExprFunctor<tvm::arith::IntervalSet (tvm::PrimExpr const&)>*) const
        at /workspace/include/tvm/node/functor.h:97
  9: tvm::tir::ExprFunctor<tvm::arith::IntervalSet (tvm::PrimExpr const&)>::InitVTable()::{lambda(tvm::runtime::ObjectRef const&, tvm::tir::ExprFunctor<tvm::arith::IntervalSet (tvm::PrimExpr const&)>*)#8}::_FUN(tvm::runtime::ObjectRef const&, tvm::tir::ExprFunctor<tvm::arith::IntervalSet (tvm::PrimExpr const&)>*)
        at /workspace/include/tvm/tir/expr_functor.h:171
  8: tvm::tir::ExprFunctor<tvm::arith::IntervalSet (tvm::PrimExpr const&)>::InitVTable()::{lambda(tvm::runtime::ObjectRef const&, tvm::tir::ExprFunctor<tvm::arith::IntervalSet (tvm::PrimExpr const&)>*)#8}::operator()(tvm::runtime::ObjectRef const&, tvm::tir::ExprFunctor<tvm::arith::IntervalSet (tvm::PrimExpr const&)>*) const
        at /workspace/include/tvm/tir/expr_functor.h:171
  7: tvm::arith::IntervalSetEvaluator::VisitExpr_(tvm::tir::AddNode const*)
        at /workspace/src/arith/int_set.cc:383
  6: tvm::arith::IntervalSet tvm::arith::IntervalSetEvaluator::VisitBinaryExpr_<tvm::tir::Add, tvm::tir::AddNode>(tvm::tir::AddNode const*)
        at /workspace/src/arith/int_set.cc:493
  5: tvm::arith::IntervalSet tvm::arith::Combine<tvm::tir::Add>(tvm::arith::Analyzer*, tvm::arith::IntervalSet, tvm::arith::IntervalSet)
        at /workspace/src/arith/int_set.cc:126
  4: tvm::arith::IntervalSetNode::IsSinglePoint() const
        at /workspace/src/arith/interval_set.h:67
  3: tvm::arith::Analyzer::CanProveEqual(tvm::PrimExpr const&, tvm::PrimExpr const&)
        at /workspace/src/arith/analyzer.cc:107
  2: tvm::operator==(tvm::PrimExpr, tvm::PrimExpr)
        at /workspace/src/tir/op/op.cc:501
  1: tvm::equal(tvm::PrimExpr, tvm::PrimExpr, tvm::Span)
        at /workspace/src/tir/op/op.cc:503
  0: tvm::BinaryOpMatchTypes(tvm::PrimExpr&, tvm::PrimExpr&, tvm::Span)
        at /workspace/src/tir/op/op.cc:163
  File "/workspace/src/tir/op/op.cc", line 163
TVMError: Cannot match type handle vs int32

[wrongtest-intellif]

Reading the cryptic error message, it seems that the IntervalSet sometimes is used to represent handle vs int, so it cans CanProveEqual - a bit weird to me, but definitely fixable with more guards

In IntervalSet, positive and negative infinity are two special values with type handle, and intset.min() and intset.max() should check whether be infinity, can not directly assume they are of integer type.

[junrushao]

That makes a lot of sense @wrongtest