TempLValueOpt : Cleanup debug_value_addr when combining a copy_addr and destroy

Author: meg-gupta

lib/SILOptimizer/Transforms/TempLValueOpt.cpp

@@ -279,14 +279,23 @@ bool TempLValueOptPass::combineCopyAndDestroy(CopyAddrInst *copyInst) {
 
   // Check if the destroy_addr is after the copy_addr and if there are no
   // memory accesses between them.
+  SmallVector<DebugValueAddrInst *, 4> debugInsts;
   for (auto iter = std::next(copyInst->getIterator());
        iter != block->end(); ++iter) {
     SILInstruction *inst = &*iter;
     if (inst == destroy) {
       copyInst->setIsTakeOfSrc(IsTake);
       destroy->eraseFromParent();
+      // Cleanup all debug_value_addr of the copy src btw the copy and destroy
+      for (auto debugInst : debugInsts) {
+        debugInst->eraseFromParent();
+      }
       return true;
     }
+    if (auto *debugInst = dyn_cast<DebugValueAddrInst>(inst)) {
+      if (debugInst->getOperand() == copyInst->getSrc())
+        debugInsts.push_back(debugInst);
+    }
     if (inst->mayReadOrWriteMemory())
       return false;
   }

test/SILOptimizer/templvalueopt_ossa.sil

@@ -282,3 +282,21 @@ bb0(%0 :@owned  $Child):
   %res = tuple ()
   return %res : $()
 }
+
+// CHECK-LABEL: sil [ossa] @cleanup_debuginsts :
+// CHECK:   copy_addr [take]
+// CHECK-NOT: debug_value_addr
+// CHECK-LABEL: } // end sil function 'cleanup_debuginsts'
+sil [ossa] @cleanup_debuginsts : $@convention(thin) <T> (@in T) -> () {
+bb0(%0 : $*T):
+  %2 = alloc_stack $T
+  debug_value_addr %0 : $*T
+  copy_addr %0 to [initialization] %2 : $*T
+  debug_value_addr %0 : $*T
+  destroy_addr %0 : $*T
+  destroy_addr %2 : $*T
+  dealloc_stack %2 : $*T
+  %78 = tuple ()
+  return %78 : $()
+}
+