roll back var equivalence changes

vyper/venom/analysis/equivalent_vars.py

@@ -1,5 +1,5 @@
-from vyper.venom.analysis import IRAnalysis
-from vyper.venom.basicblock import IRInstruction, IRLiteral, IROperand
+from vyper.venom.analysis import DFGAnalysis, IRAnalysis
+from vyper.venom.basicblock import IRVariable
 
 
 class VarEquivalenceAnalysis(IRAnalysis):
@@ -12,44 +12,29 @@ class VarEquivalenceAnalysis(IRAnalysis):
     """
 
     def analyze(self):
-        self._equivalence_set: dict[IROperand, int] = {}
+        dfg = self.analyses_cache.request_analysis(DFGAnalysis)
 
-        # dict from bags to literal values
-        self._literals: dict[int, IRLiteral] = {}
+        equivalence_set: dict[IRVariable, int] = {}
 
-        bag = 0
-        for bb in self.function.get_basic_blocks():
-            for inst in bb.instructions:
-                if inst.opcode != "store":
-                    continue
-                self._handle_store(inst, bag)
-                bag += 1
+        for bag, (var, inst) in enumerate(dfg._dfg_outputs.items()):
+            if inst.opcode != "store":
+                continue
 
-    def _handle_store(self, inst: IRInstruction, bag: int):
-        var = inst.output
-        source = inst.operands[0]
+            source = inst.operands[0]
 
-        assert var is not None  # help mypy
-        assert var not in self._equivalence_set  # invariant
+            assert var not in equivalence_set  # invariant
+            if source in equivalence_set:
+                equivalence_set[var] = equivalence_set[source]
+                continue
+            else:
+                equivalence_set[var] = bag
+                equivalence_set[source] = bag
 
-        if source in self._equivalence_set:
-            bag = self._equivalence_set[source]
-            self._equivalence_set[var] = bag
-        else:
-            self._equivalence_set[source] = bag
-            self._equivalence_set[var] = bag
-
-        if isinstance(source, IRLiteral):
-            self._literals[bag] = source
+        self._equivalence_set = equivalence_set
 
     def equivalent(self, var1, var2):
         if var1 not in self._equivalence_set:
             return False
         if var2 not in self._equivalence_set:
             return False
         return self._equivalence_set[var1] == self._equivalence_set[var2]
-
-    def get_literal(self, var):
-        if (bag := self._equivalence_set.get(var)) is None:
-            return None
-        return self._literals.get(bag)