Merge pull request #83052 from meg-gupta/fixsemarcopt

Bailout from an illegal transformation in semantic arc opts

Author: meg-gupta

lib/SILOptimizer/SemanticARC/CopyValueOpts.cpp

@@ -503,6 +503,13 @@ static bool tryJoinIfDestroyConsumingUseInSameBlock(
     if (visitedInsts.count(use->getUser()))
       return false;
 
+    // If the cvi's operand value has a non-consuming use in the same
+    // instruction which consumes the copy, bailout. NOTE:
+    // isUseBetweenInstAndBlockEnd does not check this.
+    if (user == singleCVIConsumingUse->getUser()) {
+      return false;
+    }
+
     // Ok, we have a use that isn't in our visitedInsts region. That being said,
     // we may still have a use that introduces a new BorrowScope onto our
     // copy_value's operand that overlaps with our forwarding value region. In
@@ -513,14 +520,15 @@ static bool tryJoinIfDestroyConsumingUseInSameBlock(
     // we need to only find scopes that end within the region in between the
     // singleConsumingUse (the original forwarded use) and the destroy_value. In
     // such a case, we must bail!
-    if (auto operand = BorrowingOperand(use))
+    if (auto operand = BorrowingOperand(use)) {
       if (!operand.visitScopeEndingUses([&](Operand *endScopeUse) {
             // Return false if we did see the relevant end scope instruction
             // in the block. That means that we are going to exit early and
             // return false.
             return !visitedInsts.count(endScopeUse->getUser());
           }))
         return false;
+    }
   }
 
   // Ok, we now know that we can eliminate this value.

test/SILOptimizer/semantic-arc-opts-lifetime-joining.sil

@@ -975,3 +975,42 @@ bb0:
   return %r : $()
 }
 
+sil @consume_and_borrow : $@convention(thin) (@owned Klass, @guaranteed Klass) -> ()
+sil @borrow : $@convention(thin) (@guaranteed Klass) -> ()
+sil @consume : $@convention(thin) (@owned Klass) -> ()
+sil @get_klass : $@convention(thin) () -> @owned Klass
+
+// CHECK-LABEL: sil hidden [ossa] @borrow_and_consume_copyable_test1 :
+// CHECK-NOT: copy_value
+// CHECK-LABEL: } // end sil function 'borrow_and_consume_copyable_test1'
+sil hidden [ossa] @borrow_and_consume_copyable_test1 : $@convention(thin) () -> () {
+bb0:
+  %0 = function_ref @get_klass : $@convention(thin) () -> @owned Klass
+  %1 = apply %0() : $@convention(thin) () -> @owned Klass
+  %2 = move_value [var_decl] %1
+  %3 = copy_value %2
+  %4 = function_ref @borrow : $@convention(thin) (@guaranteed Klass) -> ()
+  %5 = apply %4(%2) : $@convention(thin) (@guaranteed Klass) -> ()
+  %6 = function_ref @consume : $@convention(thin) (@owned Klass) -> ()
+  %7 = apply %6(%3) : $@convention(thin) (@owned Klass) -> ()
+  destroy_value %2
+  %9 = tuple ()
+  return %9
+}
+
+// CHECK-LABEL: sil hidden [ossa] @borrow_and_consume_copyable_test2 : 
+// CHECK: copy_value
+// CHECK-LABEL: } // end sil function 'borrow_and_consume_copyable_test2'
+sil hidden [ossa] @borrow_and_consume_copyable_test2 : $@convention(thin) () -> () {
+bb0:
+  %0 = function_ref @get_klass : $@convention(thin) () -> @owned Klass
+  %1 = apply %0() : $@convention(thin) () -> @owned Klass
+  %2 = move_value [var_decl] %1
+  %3 = copy_value %2
+  %4 = function_ref @consume_and_borrow : $@convention(thin) (@owned Klass, @guaranteed Klass) -> ()
+  %5 = apply %4(%3, %2) : $@convention(thin) (@owned Klass, @guaranteed Klass) -> ()
+  destroy_value %2
+  %7 = tuple ()
+  return %7
+}
+