[PATCH] D108482: [Clang] Fix instantiation of OpaqueValueExprs (Bug #45964)

[Jason Rice via Phabricator via cfe-commits]

ricejasonf updated this revision to Diff 369828.
ricejasonf added a comment.

I think I found a simple solution that bypasses transforming the OVE. The ArrayInitLoop always has an OVE in it so I strip it along with it in TransformInitializer.

I looked around in CodeGen and might have a better understanding of the purpose of OVEs now. The same pointer to the OVE appears twice inside the AIL. CodeGen keeps a mapping of the result of the source expression to the OVE so it emits the same result both times it encounters the OVE. Does that sound right?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D108482/new/

https://reviews.llvm.org/D108482

Files:
  clang/lib/Sema/TreeTransform.h
  clang/test/CodeGenCXX/pr45964-decomp-transform.cpp


Index: clang/test/CodeGenCXX/pr45964-decomp-transform.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGenCXX/pr45964-decomp-transform.cpp
@@ -0,0 +1,27 @@
+// RUN: %clang_cc1 -std=c++1z -triple x86_64-linux-gnu -emit-llvm -o - %s | FileCheck %s
+
+int a[1];
+// CHECK: @a = global [1 x i32] zeroinitializer
+template <int>
+void test_transform() {
+  auto [b] = a;
+}
+void (*d)(){test_transform<0>};
+// CHECK-LABEL: define {{.*}} @_Z14test_transformILi0EEvv
+// CHECK:       [[ENTRY:.*]]:
+// CHECK-NEXT:  [[ARR:%.*]] = alloca [1 x i32]
+// CHECK-NEXT:  [[BEGIN:%.*]] = getelementptr inbounds [1 x i32], [1 x i32]* [[ARR]], i64 0, i64 0
+// CHECK-NEXT:  br label %[[BODY:.*]]
+// CHECK-EMPTY:
+// CHECK-NEXT:  [[BODY]]:
+// CHECK-NEXT:  [[CUR:%.*]] = phi i64 [ 0, %[[ENTRY]] ], [ [[NEXT:%.*]], %[[BODY]] ]
+// CHECK-NEXT:  [[DEST:%.*]] = getelementptr inbounds i32, i32* [[BEGIN]], i64 [[CUR]]
+// CHECK-NEXT:  [[SRC:%.*]] = getelementptr inbounds [1 x i32], [1 x i32]* @a, i64 0, i64 [[CUR]]
+// CHECK-NEXT:  [[X:%.*]] = load i32, i32* [[SRC]]
+// CHECK-NEXT:  store i32 [[X]], i32* [[DEST]]
+// CHECK-NEXT:  [[NEXT]] = add nuw i64 [[CUR]], 1
+// CHECK-NEXT:  [[EQ:%.*]] = icmp eq i64 [[NEXT]], 1
+// CHECK-NEXT:  br i1 [[EQ]], label %[[FIN:.*]], label %[[BODY]]
+// CHECK-EMPTY:
+// CHECK-NEXT:  [[FIN]]:
+// CHECK-NEXT:  ret void
Index: clang/lib/Sema/TreeTransform.h
===================================================================
--- clang/lib/Sema/TreeTransform.h
+++ clang/lib/Sema/TreeTransform.h
@@ -3840,8 +3840,10 @@
   if (auto *FE = dyn_cast<FullExpr>(Init))
     Init = FE->getSubExpr();
 
-  if (auto *AIL = dyn_cast<ArrayInitLoopExpr>(Init))
-    Init = AIL->getCommonExpr();
+  if (auto *AIL = dyn_cast<ArrayInitLoopExpr>(Init)) {
+    OpaqueValueExpr* OVE = cast<OpaqueValueExpr>(AIL->getCommonExpr());
+    Init = OVE->getSourceExpr();
+  }
 
   if (MaterializeTemporaryExpr *MTE = dyn_cast<MaterializeTemporaryExpr>(Init))
     Init = MTE->getSubExpr();


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