Fix issue #504. Throw away some of the old work around code that's no longer needed. Update test to reflect the simpler fir that is now generated.

Author: Eric

flang/lib/Lower/ConvertExpr.cpp

@@ -276,38 +276,7 @@ class ExprLowering {
   fir::ExtendedValue genLoad(const fir::ExtendedValue &addr) {
     auto loc = getLoc();
     return addr.match(
-        [&](const fir::CharBoxValue &box) -> fir::ExtendedValue {
-          auto buffer = box.getBuffer();
-          auto len = dyn_cast<mlir::ConstantOp>(box.getLen().getDefiningOp());
-          if (!len) {
-            // TODO: return an emboxchar?
-            // Not sure an emboxchar would help, it would simply
-            // indirects the memory reference, so it fakes the load and then
-            // makes it harder to work with the character due to the
-            // indirection. Solutions I see are:
-            //  1. create a temp and returns a CharBoxValue pointing to it.
-            //  2. create a dynamic vector fir type that can abstract 1.
-            mlir::emitError(loc, "cannot load a variable length char");
-            return {};
-          }
-          auto lenAttr = len.value().dyn_cast<mlir::IntegerAttr>();
-          if (!lenAttr) {
-            mlir::emitError(loc, "length must be integer");
-            return {};
-          }
-          auto lenConst = lenAttr.getValue().getSExtValue();
-          fir::SequenceType::Shape shape = {lenConst};
-          auto baseTy =
-              Fortran::lower::CharacterExprHelper::getCharacterType(box);
-          auto charTy =
-              builder.getRefType(fir::SequenceType::get(shape, baseTy));
-          auto casted = builder.createConvert(loc, charTy, buffer);
-          auto val = builder.create<fir::LoadOp>(loc, casted);
-          return fir::CharBoxValue{val, box.getLen()};
-        },
-        [&](const fir::CharArrayBoxValue &v) -> fir::ExtendedValue {
-          TODO("loading character array");
-        },
+        [](const fir::CharBoxValue &box) -> fir::ExtendedValue { return box; },
         [&](const fir::UnboxedValue &v) -> fir::ExtendedValue {
           return builder.create<fir::LoadOp>(loc, fir::getBase(v));
         },

flang/test/Lower/intrinsics.f90

@@ -182,13 +182,20 @@ end subroutine iand_test
 subroutine ichar_test(c)
   character(1) :: c
   character :: str(10)
-  ! CHECK: %[[BOX:.*]] = fir.load %{{.*}} : !fir.ref<!fir.char<1>>
-  ! CHECK: %{{.*}} = fir.convert %[[BOX]] : (!fir.char<1>) -> i32
+  ! CHECK-DAG: %[[unbox:.*]]:2 = fir.unboxchar
+  ! CHECK-DAG: %[[J:.*]] = fir.alloca i32 {name = "{{.*}}Ej"}
+  ! CHECK-DAG: %[[STR:.*]] = fir.alloca !fir.array{{.*}} {name = "{{.*}}Estr"}
+  ! CHECK: %[[BOX:.*]] = fir.load %[[unbox]]#0 : !fir.ref<!fir.char<1>>
+  ! CHECK: = fir.convert %[[BOX]] : (!fir.char<1>) -> i32
   print *, ichar(c)
+  ! CHECK: fir.call @{{.*}}EndIoStatement
 
-  ! CHECK: %[[ARRV:.*]] = fir.extract_value %{{.*}}, %{{.*}} : (!fir.array<1x!fir.char<1>>, i32) -> !fir.char<1>
-  ! CHECK: %{{.*}} = fir.convert %[[ARRV]] : (!fir.char<1>) -> i32
+  ! CHECK: %{{.*}} = fir.load %[[J]] : !fir.ref<i32>
+  ! CHECK: %[[ptr:.*]] = fir.coordinate_of %[[STR]], %
+  ! CHECK: %[[cast:.*]] = fir.convert %[[ptr]]
+  ! CHECK: fir.load %[[cast]] : !fir.ref<!fir.char<1>>
   print *, ichar(str(J))
+  ! CHECK: fir.call @{{.*}}EndIoStatement
 end subroutine
 
 ! IEOR