From 6ed397928de76b1f106f16a58d27c2f9aad82f4e Mon Sep 17 00:00:00 2001
From: Edward Caunt <ed@devitocodes.com>
Date: Tue, 24 Sep 2024 16:47:00 +0100
Subject: [PATCH] compiler: Tweak renaming to operate after first encountered
 and warn user

---
 devito/ir/equations/algorithms.py | 25 ++++++++++++++++---------
 devito/ir/support/symregistry.py  |  6 +++++-
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/devito/ir/equations/algorithms.py b/devito/ir/equations/algorithms.py
index ab7f9745e8..c8f207855b 100644
--- a/devito/ir/equations/algorithms.py
+++ b/devito/ir/equations/algorithms.py
@@ -10,6 +10,7 @@
 from devito.types.basic import AbstractFunction
 from devito.types.dimension import MultiSubDimension
 from devito.data.allocators import DataReference
+from devito.logger import warning
 
 __all__ = ['dimension_sort', 'lower_exprs', 'concretize_subdims']
 
@@ -184,7 +185,7 @@ def concretize_subdims(exprs, **kwargs):
         dimensions = tuple(mapper.get(d, d) for d in f.dimensions)
         if dimensions != f.dimensions:
             # A dimension has been rebuilt, so build a mapper for Indexed
-            mapper[f.indexed] = f._rebuild(dimensions=dimensions, function=None).indexed
+            mapper[f.indexed] = f._rebuild(dimensions=dimensions).indexed
 
     processed = [uxreplace(e, mapper) for e in exprs]
 
@@ -218,9 +219,8 @@ def _(d, mapper, rebuilt, sregistry):
         # Already have a substitution for this dimension
         return
 
-    tkns = [tkn._rebuild(name=sregistry.make_name(prefix=tkn.name))
-            for tkn in d.tkns]
-    tkns_subs = {tkn0: tkn1 for tkn0, tkn1 in zip(d.tkns, tkns)}
+    tkns_subs = {tkn: tkn._rebuild(name=sregistry.make_name(prefix=tkn.name))
+                 for tkn in d.tkns}
     left, right = [mM.subs(tkns_subs) for mM in (d.symbolic_min, d.symbolic_max)]
     thickness = tuple((v, d._thickness_map[k]) for k, v in tkns_subs.items())
 
@@ -277,15 +277,22 @@ def _(d, mapper, rebuilt, sregistry):
             rebuilt[idim0] = idim1 = idim0._rebuild(name=iname)
 
         kwargs['implicit_dimension'] = idim1
-        fkwargs.update({'dimensions': (idim1,) + d.functions.dimensions[1:],
-                        'halo': None,
-                        'padding': None})
+        fkwargs['dimensions'] = (idim1,) + d.functions.dimensions[1:]
 
     if d.functions in rebuilt:
         functions = rebuilt[d.functions]
     else:
-        fkwargs.update({'name': sregistry.make_name(prefix=d.functions.name),
-                        'function': None})
+        # Increment every instance of this name after the first encountered
+        fname = sregistry.make_name(prefix=d.functions.name, increment_first=False)
+        # Warn the user if name has been changed, since this will affect overrides
+        if fname != d.functions.name:
+            fkwargs['name'] = fname
+            warning("%s <%s> renamed as '%s'. Consider assigning a unique name to %s." %
+                    (str(d.functions), id(d.functions), fname, d.functions.name))
+
+        fkwargs.update({'function': None,
+                        'halo': None,
+                        'padding': None})
 
         # Data in MultiSubDimension function may not have been touched at this point,
         # in which case do not use an allocator, as there is nothing to allocate, and
diff --git a/devito/ir/support/symregistry.py b/devito/ir/support/symregistry.py
index f5233d8143..8149ab22d5 100644
--- a/devito/ir/support/symregistry.py
+++ b/devito/ir/support/symregistry.py
@@ -30,7 +30,7 @@ def __init__(self):
         # passes, to maximize symbol (especially Dimension) reuse
         self.caches = {}
 
-    def make_name(self, prefix=None):
+    def make_name(self, prefix=None, increment_first=True):
         # By default we're creating a new symbol
         if prefix is None:
             prefix = self._symbol_prefix
@@ -40,6 +40,10 @@ def make_name(self, prefix=None):
         except KeyError:
             counter = self.counters.setdefault(prefix, generator())
 
+            # Only increment symbol names after the first encountered
+            if not increment_first:
+                return prefix
+
         return "%s%d" % (prefix, counter())
 
     def make_npthreads(self, size):