[flang] Don't use-associate intrinsics

When an intrinsic is referenced in a module scope, a symbol for it is
added. When that module is USEd, the intrinsic should not be included.
Otherwise we can get ambiguous reference errors with the same intrinsic
coming from two difference modules.

Differential Revision: https://reviews.llvm.org/D83905

flang/lib/Semantics/resolve-names.cpp

@@ -2310,6 +2310,7 @@ void ModuleVisitor::Post(const parser::UseStmt &x) {
     }
     for (const auto &[name, symbol] : *useModuleScope_) {
       if (symbol->attrs().test(Attr::PUBLIC) &&
+          !symbol->attrs().test(Attr::INTRINSIC) &&
           !symbol->detailsIf<MiscDetails>()) {
         if (useNames.count(name) == 0) {
           auto *localSymbol{FindInScope(currScope(), name)};

flang/test/Semantics/modfile30.f90

@@ -42,7 +42,6 @@ module m2
 ! type(t),parameter::a=t()
 !end
 
-! Don't write out intrinsics
 module m3a
   integer, parameter :: i4 = selected_int_kind(9)
 end
@@ -60,7 +59,6 @@ module m3b
 !Expect: m3b.mod
 !module m3b
 ! use m3a,only:i4
-! use m3a,only:selected_int_kind
 ! integer(4)::j
 !end
 
@@ -82,7 +80,6 @@ module m4b
 !Expect: m4b.mod
 !module m4b
 ! use m4a,only:a
-! use m4a,only:achar
 ! character(1_4,1),parameter::b="\001"
 !end
 

flang/test/Semantics/resolve14.f90

@@ -3,20 +3,30 @@ module m1
   integer :: x
   integer :: y
   integer :: z
+  integer, parameter :: k1 = selected_int_kind(9)
 end
 module m2
   real :: y
   real :: z
   real :: w
+  integer, parameter :: k2 = selected_int_kind(9)
 end
 
-use m1, xx => x, y => z
-use m2
-volatile w
-!ERROR: Cannot change CONTIGUOUS attribute on use-associated 'w'
-contiguous w
-!ERROR: 'z' is use-associated from module 'm2' and cannot be re-declared
-integer z
-!ERROR: Reference to 'y' is ambiguous
-y = 1
+program p1
+  use m1
+  use m2
+  ! check that selected_int_kind is not use-associated
+  integer, parameter :: k = selected_int_kind(9)
+end
+
+program p2
+  use m1, xx => x, y => z
+  use m2
+  volatile w
+  !ERROR: Cannot change CONTIGUOUS attribute on use-associated 'w'
+  contiguous w
+  !ERROR: 'z' is use-associated from module 'm2' and cannot be re-declared
+  integer z
+  !ERROR: Reference to 'y' is ambiguous
+  y = 1
 end