Delete debug_value_addr of stack location, if a debug_value of the RunningVal is already found

Author: meg-gupta

lib/SILOptimizer/Transforms/SILMem2Reg.cpp

@@ -323,8 +323,10 @@ promoteDebugValueAddr(DebugValueAddrInst *DVAI, SILValue Value, SILBuilder &B) {
   // Avoid inserting the same debug_value twice.
   for (Operand *Use : Value->getUses())
     if (auto *DVI = dyn_cast<DebugValueInst>(Use->getUser()))
-      if (*DVI->getVarInfo() == *DVAI->getVarInfo())
+      if (*DVI->getVarInfo() == *DVAI->getVarInfo()) {
+        DVAI->eraseFromParent();
         return;
+      }
   B.setInsertionPoint(DVAI);
   B.setCurrentDebugScope(DVAI->getDebugScope());
   B.createDebugValue(DVAI->getLoc(), Value, *DVAI->getVarInfo());

test/SILOptimizer/mem2reg_ossa_nontrivial.sil

@@ -613,3 +613,20 @@ bb0(%0 : @owned $(Builtin.BridgeObject, Builtin.Int32)):
   %7 = tuple ()
   return %7 : $()
 }
+
+// CHECK-LABEL: sil [ossa] @multiple_debug_value :
+// CHECK-NOT: alloc_stack
+// CHECK-LABEL: } // end sil function 'multiple_debug_value'
+sil [ossa] @multiple_debug_value : $@convention(thin) (@owned Klass) -> () {
+bb0(%0 : @owned $Klass):
+  debug_value %0 : $Klass
+  %2 = alloc_stack $Klass
+  store %0 to [init] %2 : $*Klass
+  debug_value_addr %2 : $*Klass
+  %5 = load [take] %2 : $*Klass
+  destroy_value %5 : $Klass
+  dealloc_stack %2 : $*Klass
+  %7 = tuple ()
+  return %7 : $()
+}
+