[NFC][flang] Remove unused code in lowerExplicitLowerBounds

[peixin]

Summary

There is no need to lower the implicit lower bounds for assumed-shape
array in lowerExplicitLowerBounds. Remove the unused code.

[clementval]

Did you test that on fir-dev? Since we are in the middle of upstreaming I would rather not start removing code right now.

[peixin]

In D122280#3401547, @clementval wrote:

We are in the middle of upstreaming and this might be used later so I would prefer to not remove it now.

I also checked fir-dev. Actually, this is the incorrect code. Fortran 2018 section 8.5.8.3 point 3 is for assumed-shape array, then spec->lbound().isColon() should be true. If spec->lbound().isColon() is false, the array would be assumed-size array, and this function will get early return since box.lboundIsAllOnes() is true. That's why this code is never used.

If this patch affects the progress of upstreaming, we can wait for it.

[clementval]

In D122280#3401657, @peixin wrote:

In D122280#3401547, @clementval wrote:

We are in the middle of upstreaming and this might be used later so I would prefer to not remove it now.

I also checked fir-dev. Actually, this is the incorrect code. Fortran 2018 section 8.5.8.3 point 3 is for assumed-shape array, then spec->lbound().isColon() should be true. If spec->lbound().isColon() is false, the array would be assumed-size array, and this function will get early return since box.lboundIsAllOnes() is true. That's why this code is never used.

If this patch affects the progress of upstreaming, we can wait for it.

So please make the change in fir-dev first otherwise we might reupstream this later.

[peixin]

In D122280#3401686, @clementval wrote:

In D122280#3401657, @peixin wrote:

In D122280#3401547, @clementval wrote:

We are in the middle of upstreaming and this might be used later so I would prefer to not remove it now.

I also checked fir-dev. Actually, this is the incorrect code. Fortran 2018 section 8.5.8.3 point 3 is for assumed-shape array, then spec->lbound().isColon() should be true. If spec->lbound().isColon() is false, the array would be assumed-size array, and this function will get early return since box.lboundIsAllOnes() is true. That's why this code is never used.

If this patch affects the progress of upstreaming, we can wait for it.

So please make the change in fir-dev first otherwise we might reupstream this later.

OK. Got the rules. Submitted (https://github.com/flang-compiler/f18-llvm-project/pull/1545) in fir-dev.

[clementval]

In D122280#3401707, @peixin wrote:

In D122280#3401686, @clementval wrote:

In D122280#3401657, @peixin wrote:

In D122280#3401547, @clementval wrote:

We are in the middle of upstreaming and this might be used later so I would prefer to not remove it now.

I also checked fir-dev. Actually, this is the incorrect code. Fortran 2018 section 8.5.8.3 point 3 is for assumed-shape array, then spec->lbound().isColon() should be true. If spec->lbound().isColon() is false, the array would be assumed-size array, and this function will get early return since box.lboundIsAllOnes() is true. That's why this code is never used.

If this patch affects the progress of upstreaming, we can wait for it.

So please make the change in fir-dev first otherwise we might reupstream this later.

OK. Got the rules. Submitted (https://github.com/flang-compiler/f18-llvm-project/pull/1545) in fir-dev.

Thanks a lot. We should be done with this pretty soon.

[jeanPerier]

LGTM

[peixin]

Thanks @clementval and @jeanPerier . I will land this after the one in fir-dev is mereged.

[clementval]

You can go ahead.

flang/lib/Lower/ConvertVariable.cpp

if (box.isStaticArray()) {
     return;
   }
   for (const Fortran::semantics::ShapeSpec *spec : box.dynamicBound()) {
     if (auto low = spec->lbound().GetExplicit()) {
       auto expr = Fortran::lower::SomeExpr{*low};
       mlir::Value lb = builder.createConvert(
           loc, idxTy, genScalarValue(converter, loc, expr, symMap, stmtCtx));
       result.emplace_back(lb);
-    } else if (!spec->lbound().isColon()) {
-      // Implicit lower bound is 1 (Fortran 2018 section 8.5.8.3 point 3.)
-      result.emplace_back(builder.createIntegerConstant(loc, idxTy, 1));
     }
   }
   assert(result.empty() || result.size() == box.dynamicBound().size());
 }
 
 /// Lower explicit extents into \p result if this is an explicit-shape or
 /// assumed-size array. Does nothing if this is not an explicit-shape or
 /// assumed-size array.