[clang] [clang] Fix parenthesized list initialization of arrays not working with `new` (PR #76976)

Alan Zhao via cfe-commits cfe-commits at lists.llvm.org
Tue Jan 9 17:26:49 PST 2024


https://github.com/alanzhao1 updated https://github.com/llvm/llvm-project/pull/76976

>From ee4e3c8634bb876166ee753a4ebcbf3c1699a175 Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Wed, 3 Jan 2024 12:29:21 -0800
Subject: [PATCH 1/6] [clang] Fix parenthesized list initialization of arrays
 not working with `new`

This bug is caused by parenthesized list initialization not being
implemented in `CodeGenFunction::EmitNewArrayInitializer(...)`.

Parenthesized list initialization of `struct`s  with `operator new`
already works in Clang and is not affected by this bug.

Additionally, fix the test new-delete.cpp as it incorrectly assumes that
using parentheses with operator new to initialize arrays is illegal for
C++ versions >= C++17.

Fixes #68198
---
 clang/docs/ReleaseNotes.rst                |  3 +
 clang/lib/CodeGen/CGExprCXX.cpp            | 17 ++---
 clang/lib/Sema/SemaExprCXX.cpp             |  6 +-
 clang/test/CodeGen/paren-list-agg-init.cpp | 72 ++++++++++++++++++++++
 clang/test/SemaCXX/new-delete.cpp          | 20 +++---
 5 files changed, 98 insertions(+), 20 deletions(-)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index c7bf162426a68c..211fd62a1ee85f 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -844,6 +844,9 @@ Bug Fixes to C++ Support
 - Fix crash when parsing nested requirement. Fixes:
   (`#73112 <https://github.com/llvm/llvm-project/issues/73112>`_)
 
+- Clang now allows parenthesized initialization of arrays in `operator new[]`.
+  Fixes: (`#68198 <https://github.com/llvm/llvm-project/issues/68198>`_)
+
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
 - Fixed an import failure of recursive friend class template.
diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp
index 98ae56e2df8818..72c61bfb5ec344 100644
--- a/clang/lib/CodeGen/CGExprCXX.cpp
+++ b/clang/lib/CodeGen/CGExprCXX.cpp
@@ -1038,11 +1038,13 @@ void CodeGenFunction::EmitNewArrayInitializer(
     return true;
   };
 
+  const InitListExpr *ILE = dyn_cast<InitListExpr>(Init);
+  const CXXParenListInitExpr *CPLIE = dyn_cast<CXXParenListInitExpr>(Init);
   // If the initializer is an initializer list, first do the explicit elements.
-  if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
+  if (ILE || CPLIE) {
     // Initializing from a (braced) string literal is a special case; the init
     // list element does not initialize a (single) array element.
-    if (ILE->isStringLiteralInit()) {
+    if (ILE && ILE->isStringLiteralInit()) {
       // Initialize the initial portion of length equal to that of the string
       // literal. The allocation must be for at least this much; we emitted a
       // check for that earlier.
@@ -1073,7 +1075,7 @@ void CodeGenFunction::EmitNewArrayInitializer(
       return;
     }
 
-    InitListElements = ILE->getNumInits();
+    InitListElements = ILE ? ILE->getNumInits() : CPLIE->getInitExprs().size();
 
     // If this is a multi-dimensional array new, we will initialize multiple
     // elements with each init list element.
@@ -1101,7 +1103,8 @@ void CodeGenFunction::EmitNewArrayInitializer(
     }
 
     CharUnits StartAlign = CurPtr.getAlignment();
-    for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) {
+    ArrayRef<Expr *> InitExprs = ILE ? ILE->inits() : CPLIE->getInitExprs();
+    for (unsigned i = 0; i < InitExprs.size(); ++i) {
       // Tell the cleanup that it needs to destroy up to this
       // element.  TODO: some of these stores can be trivially
       // observed to be unnecessary.
@@ -1111,8 +1114,8 @@ void CodeGenFunction::EmitNewArrayInitializer(
       // FIXME: If the last initializer is an incomplete initializer list for
       // an array, and we have an array filler, we can fold together the two
       // initialization loops.
-      StoreAnyExprIntoOneUnit(*this, ILE->getInit(i),
-                              ILE->getInit(i)->getType(), CurPtr,
+      Expr *IE = InitExprs[i];
+      StoreAnyExprIntoOneUnit(*this, IE, IE->getType(), CurPtr,
                               AggValueSlot::DoesNotOverlap);
       CurPtr = Address(Builder.CreateInBoundsGEP(
                            CurPtr.getElementType(), CurPtr.getPointer(),
@@ -1122,7 +1125,7 @@ void CodeGenFunction::EmitNewArrayInitializer(
     }
 
     // The remaining elements are filled with the array filler expression.
-    Init = ILE->getArrayFiller();
+    Init = ILE ? ILE->getArrayFiller() : CPLIE->getArrayFiller();
 
     // Extract the initializer for the individual array elements by pulling
     // out the array filler from all the nested initializer lists. This avoids
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 4ae04358d5df7c..71e420648ce7af 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -1947,11 +1947,11 @@ Sema::ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
 }
 
 static bool isLegalArrayNewInitializer(CXXNewInitializationStyle Style,
-                                       Expr *Init) {
+                                       Expr *Init, bool IsCPlusPlus20) {
   if (!Init)
     return true;
   if (ParenListExpr *PLE = dyn_cast<ParenListExpr>(Init))
-    return PLE->getNumExprs() == 0;
+    return IsCPlusPlus20 || PLE->getNumExprs() == 0;
   if (isa<ImplicitValueInitExpr>(Init))
     return true;
   else if (CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Init))
@@ -2403,7 +2403,7 @@ ExprResult Sema::BuildCXXNew(SourceRange Range, bool UseGlobal,
   // Array 'new' can't have any initializers except empty parentheses.
   // Initializer lists are also allowed, in C++11. Rely on the parser for the
   // dialect distinction.
-  if (ArraySize && !isLegalArrayNewInitializer(InitStyle, Initializer)) {
+  if (ArraySize && !isLegalArrayNewInitializer(InitStyle, Initializer, getLangOpts().CPlusPlus20)) {
     SourceRange InitRange(Exprs.front()->getBeginLoc(),
                           Exprs.back()->getEndLoc());
     Diag(StartLoc, diag::err_new_array_init_args) << InitRange;
diff --git a/clang/test/CodeGen/paren-list-agg-init.cpp b/clang/test/CodeGen/paren-list-agg-init.cpp
index 0e68beb5c37066..9618b6ddf14558 100644
--- a/clang/test/CodeGen/paren-list-agg-init.cpp
+++ b/clang/test/CodeGen/paren-list-agg-init.cpp
@@ -513,3 +513,75 @@ namespace gh61567 {
     I(0);
   }
 }
+
+namespace gh68198 {
+  // CHECK: define {{.*}} void @{{.*foo25.*}} {
+  // CHECK-NEXT: entry
+  // CHECK-NEXT: [[ARR_8:%.*arr8.*]] = alloca ptr, align 8
+  // CHECK-NEXT: [[CALL_PTR:%.*]] = call noalias noundef nonnull ptr @_Znam(i64 noundef 8)
+  // CHECK-NEXT: store i32 1, ptr [[CALL_PTR]], align 4
+  // CHECK-NEXT: [[ARRAY_EXP_NEXT:%.*]] = getelementptr inbounds i32, ptr [[CALL_PTR]], i64 1
+  // CHECK-NEXT: store i32 2, ptr [[ARRAY_EXP_NEXT]], align 4
+  // CHECK-NEXT: [[ARRAY_EXP_NEXT1:%.*]] = getelementptr inbounds i32, ptr [[ARRAY_EXP_NEXT]], i64 1
+  // CHECK-NEXT: store ptr [[CALL_PTR]], ptr %arr8, align 8
+  // CHECK-NEXT: ret void
+  void foo25() {
+    int* arr8 = new int[](1, 2);
+  }
+
+  // CHECK: define {{.*}} void @{{.*foo26.*}} {
+  // CHECK-NEXT: entry
+  // CHECK-NEXT: [[ARR_9:%.*arr9.*]] = alloca ptr, align 8
+  // CHECK-NEXT: [[CALL_PTR:%.*]] = call noalias noundef nonnull ptr @_Znam(i64 noundef 16) #7
+  // CHECK-NEXT: store i32 1, ptr [[CALL_PTR]], align 4
+  // CHECK-NEXT: [[ARRAY_EXP_NEXT:%.*]] = getelementptr inbounds i32, ptr [[CALL_PTR]], i64 1
+  // CHECK-NEXT: store i32 2, ptr [[ARRAY_EXP_NEXT]], align 4
+  // CHECK-NEXT: [[ARRAY_EXP_NEXT1:%.*]] = getelementptr inbounds i32, ptr [[ARRAY_EXP_NEXT]], i64 1
+  // CHECK-NEXT: call void @llvm.memset.p0.i64(ptr align 4 [[ARRAY_EXP_NEXT1]], i8 0, i64 8, i1 false)
+  // CHECK-NEXT: store ptr [[CALL_PTR]], ptr [[ARR_9]], align 8
+  // CHECK-NEXT: ret void
+  void foo26() {
+    int* arr9 = new int[4](1, 2);
+  }
+
+  // CHECK: define {{.*}} void @{{.*foo27.*}} {
+  // CHECK-NEXT: entry
+  // CHECK-NEXT: [[ARR_10:%.*arr10.*]] = alloca ptr, align 8
+  // CHECK-NEXT: [[CALL_PTR]] = call noalias noundef nonnull ptr @_Znam(i64 noundef 16)
+  // CHECK-NEXT: [[ARRAYINIT_BEGIN:%.*]] = getelementptr inbounds [2 x i32], ptr [[CALL]], i64 0, i64 0
+  // CHECK-NEXT: store i32 1, ptr [[ARRAYINIT_BEGIN]], align 4
+  // CHECK-NEXT: [[ARRAYINIT_ELEMENT:%.*]] = getelementptr inbounds i32, ptr [[ARRAYINIT_BEGIN]], i64 1
+  // CHECK-NEXT: store i32 2, ptr [[ARRAYINIT_ELEMENT]], align 4
+  // CHECK-NEXT: [[ARRAY_EXP_NEXT:%.*]] = getelementptr inbounds [2 x i32], ptr %call, i64 1
+  // CHECK-NEXT: [[ARRAYINIT_BEGIN1:%.*]] = getelementptr inbounds [2 x i32], ptr [[ARRAY_EXP_NEXT]], i64 0, i64 0
+  // CHECK-NEXT: store i32 3, ptr [[ARRAYINIT_BEGIN1]], align 4
+  // CHECK-NEXT: [[ARRAYINIT_ELEMENT2:%.*]] = getelementptr inbounds i32, ptr [[ARRAYINIT_BEGIN1]], i64 1
+  // CHECK-NEXT: store i32 4, ptr [[ARRAYINIT_ELEMENT2]], align 4
+  // CHECK-NEXT: [[ARRAY_EXP_NEXT3:%.*]] = getelementptr inbounds [2 x i32], ptr [[ARRAY_EXP_NEXT]], i64 1
+  // CHECK-NEXT: store ptr [[CALL_PTR]], ptr [[ARR_10]], align 8
+  // CHECK-NEXT: ret void
+  void foo27() {
+    void* arr10 = new int[][2]({1, 2}, {3, 4});
+  }
+
+  // CHECK: define {{.*}} void @{{.*foo28.*}} {
+  // CHECK-NEXT: entry
+  // CHECK-NEXT: [[ARR_11:%.*arr11.*]] = alloca ptr, align 8
+  // CHECK-NEXT: [[CALL_PTR]] = call noalias noundef nonnull ptr @_Znam(i64 noundef 32)
+  // CHECK-NEXT: [[ARRAYINIT_BEGIN:%.*]] = getelementptr inbounds [2 x i32], ptr [[CALL]], i64 0, i64 0
+  // CHECK-NEXT: store i32 5, ptr [[ARRAYINIT_BEGIN]], align 4
+  // CHECK-NEXT: [[ARRAYINIT_ELEMENT:%.*]] = getelementptr inbounds i32, ptr [[ARRAYINIT_BEGIN]], i64 1
+  // CHECK-NEXT: store i32 6, ptr [[ARRAYINIT_ELEMENT]], align 4
+  // CHECK-NEXT: [[ARRAY_EXP_NEXT:%.*]] = getelementptr inbounds [2 x i32], ptr %call, i64 1
+  // CHECK-NEXT: [[ARRAYINIT_BEGIN1:%.*]] = getelementptr inbounds [2 x i32], ptr [[ARRAY_EXP_NEXT]], i64 0, i64 0
+  // CHECK-NEXT: store i32 7, ptr [[ARRAYINIT_BEGIN1]], align 4
+  // CHECK-NEXT: [[ARRAYINIT_ELEMENT2:%.*]] = getelementptr inbounds i32, ptr [[ARRAYINIT_BEGIN1]], i64 1
+  // CHECK-NEXT: store i32 8, ptr [[ARRAYINIT_ELEMENT2]], align 4
+  // CHECK-NEXT: [[ARRAY_EXP_NEXT3:%.*]] = getelementptr inbounds [2 x i32], ptr [[ARRAY_EXP_NEXT]], i64 1
+  // CHECK-NEXT: call void @llvm.memset.p0.i64(ptr align 4 [[ARRAY_EXP_NEXT3]], i8 0, i64 16, i1 false)
+  // CHECK-NEXT: store ptr [[CALL_PTR]], ptr [[ARR_11]], align 8
+  // CHECK-NEXT: ret void
+  void foo28() {
+    void* arr11 = new int[4][2]({5, 6}, {7, 8});
+  }
+}
diff --git a/clang/test/SemaCXX/new-delete.cpp b/clang/test/SemaCXX/new-delete.cpp
index 0270e42b7389fe..ec406260b6a391 100644
--- a/clang/test/SemaCXX/new-delete.cpp
+++ b/clang/test/SemaCXX/new-delete.cpp
@@ -1,7 +1,7 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++98
-// RUN: %clang_cc1 -fsyntax-only -verify %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++11
-// RUN: %clang_cc1 -fsyntax-only -verify %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++14
-// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx17 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null %std_cxx17-
+// RUN: %clang_cc1 -fsyntax-only -verify=expected,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++11
+// RUN: %clang_cc1 -fsyntax-only -verify=expected,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++14
+// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx17,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++17
+// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx17 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++20
 
 // FIXME Location is (frontend)
 // cxx17-note@*:* {{candidate function not viable: requires 2 arguments, but 3 were provided}}
@@ -340,23 +340,23 @@ namespace PR5918 { // Look for template operator new overloads.
 namespace Test1 {
 
 void f() {
-  (void)new int[10](1, 2); // expected-error {{array 'new' cannot have initialization arguments}}
+  (void)new int[10](1, 2); // precxx20-error {{array 'new' cannot have initialization arguments}}
 
   typedef int T[10];
-  (void)new T(1, 2); // expected-error {{array 'new' cannot have initialization arguments}}
+  (void)new T(1, 2); // precxx20-error {{array 'new' cannot have initialization arguments}}
 }
 
 template<typename T>
 void g(unsigned i) {
-  (void)new T[1](i); // expected-error {{array 'new' cannot have initialization arguments}}
+  (void)new T[1](i); // precxx20-error {{array 'new' cannot have initialization arguments}}
 }
 
 template<typename T>
 void h(unsigned i) {
-  (void)new T(i); // expected-error {{array 'new' cannot have initialization arguments}}
+  (void)new T(i); // precxx20-error {{array 'new' cannot have initialization arguments}}
 }
 template void h<unsigned>(unsigned);
-template void h<unsigned[10]>(unsigned); // expected-note {{in instantiation of function template specialization 'Test1::h<unsigned int[10]>' requested here}}
+template void h<unsigned[10]>(unsigned); // precxx20-note {{in instantiation of function template specialization 'Test1::h<unsigned int[10]>' requested here}}
 
 }
 
@@ -556,7 +556,7 @@ namespace P12023 {
 
   int main()
   {
-    CopyCounter* f = new CopyCounter[10](CopyCounter()); // expected-error {{cannot have initialization arguments}}
+    CopyCounter* f = new CopyCounter[10](CopyCounter()); // precxx20-error {{cannot have initialization arguments}}
       return 0;
   }
 }

>From ccdf700474cba4b77e2e0cf7029d673cca65840f Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Thu, 4 Jan 2024 09:06:43 -0800
Subject: [PATCH 2/6] fix accidentally deleted line in new-delete.cpp

---
 clang/test/SemaCXX/new-delete.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/clang/test/SemaCXX/new-delete.cpp b/clang/test/SemaCXX/new-delete.cpp
index ec406260b6a391..2db32938f957fb 100644
--- a/clang/test/SemaCXX/new-delete.cpp
+++ b/clang/test/SemaCXX/new-delete.cpp
@@ -1,3 +1,4 @@
+// RUN: %clang_cc1 -fsyntax-only -verify=expected,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++98
 // RUN: %clang_cc1 -fsyntax-only -verify=expected,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++11
 // RUN: %clang_cc1 -fsyntax-only -verify=expected,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++14
 // RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx17,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++17

>From 1877e21590aa5c16481b78f1a88ccede5dac4194 Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Thu, 4 Jan 2024 09:08:44 -0800
Subject: [PATCH 3/6] fix clang format issue

---
 clang/lib/Sema/SemaExprCXX.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 71e420648ce7af..90e0dcb35af277 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -2403,7 +2403,8 @@ ExprResult Sema::BuildCXXNew(SourceRange Range, bool UseGlobal,
   // Array 'new' can't have any initializers except empty parentheses.
   // Initializer lists are also allowed, in C++11. Rely on the parser for the
   // dialect distinction.
-  if (ArraySize && !isLegalArrayNewInitializer(InitStyle, Initializer, getLangOpts().CPlusPlus20)) {
+  if (ArraySize && !isLegalArrayNewInitializer(InitStyle, Initializer,
+                                               getLangOpts().CPlusPlus20)) {
     SourceRange InitRange(Exprs.front()->getBeginLoc(),
                           Exprs.back()->getEndLoc());
     Diag(StartLoc, diag::err_new_array_init_args) << InitRange;

>From 5610f3018abbf8076c80c8800b89f429cb8d8fb4 Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Thu, 4 Jan 2024 11:17:42 -0800
Subject: [PATCH 4/6] use range-based for loop

---
 clang/lib/CodeGen/CGExprCXX.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp
index 72c61bfb5ec344..dd93bcfc57b93c 100644
--- a/clang/lib/CodeGen/CGExprCXX.cpp
+++ b/clang/lib/CodeGen/CGExprCXX.cpp
@@ -1104,7 +1104,8 @@ void CodeGenFunction::EmitNewArrayInitializer(
 
     CharUnits StartAlign = CurPtr.getAlignment();
     ArrayRef<Expr *> InitExprs = ILE ? ILE->inits() : CPLIE->getInitExprs();
-    for (unsigned i = 0; i < InitExprs.size(); ++i) {
+    unsigned i = 0;
+    for (Expr *IE : InitExprs) {
       // Tell the cleanup that it needs to destroy up to this
       // element.  TODO: some of these stores can be trivially
       // observed to be unnecessary.
@@ -1114,14 +1115,13 @@ void CodeGenFunction::EmitNewArrayInitializer(
       // FIXME: If the last initializer is an incomplete initializer list for
       // an array, and we have an array filler, we can fold together the two
       // initialization loops.
-      Expr *IE = InitExprs[i];
       StoreAnyExprIntoOneUnit(*this, IE, IE->getType(), CurPtr,
                               AggValueSlot::DoesNotOverlap);
       CurPtr = Address(Builder.CreateInBoundsGEP(
                            CurPtr.getElementType(), CurPtr.getPointer(),
                            Builder.getSize(1), "array.exp.next"),
                        CurPtr.getElementType(),
-                       StartAlign.alignmentAtOffset((i + 1) * ElementSize));
+                       StartAlign.alignmentAtOffset((++i) * ElementSize));
     }
 
     // The remaining elements are filled with the array filler expression.

>From 471ffa0c098e5c7a66e49567bc31d2de16cbbb67 Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Tue, 9 Jan 2024 13:53:24 -0800
Subject: [PATCH 5/6] fix initialization with string literals and dynamically
 sized arrays

---
 clang/lib/CodeGen/CGExprCXX.cpp            | 32 ++++++----
 clang/lib/Sema/SemaInit.cpp                | 14 ++---
 clang/test/CodeGen/paren-list-agg-init.cpp | 31 +++-------
 clang/test/CodeGenCXX/new-array-init.cpp   | 72 +++++++++++++++++++++-
 clang/test/SemaCXX/new-delete.cpp          | 12 +++-
 5 files changed, 115 insertions(+), 46 deletions(-)

diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp
index dd93bcfc57b93c..947553cb2ef2a3 100644
--- a/clang/lib/CodeGen/CGExprCXX.cpp
+++ b/clang/lib/CodeGen/CGExprCXX.cpp
@@ -1040,11 +1040,12 @@ void CodeGenFunction::EmitNewArrayInitializer(
 
   const InitListExpr *ILE = dyn_cast<InitListExpr>(Init);
   const CXXParenListInitExpr *CPLIE = dyn_cast<CXXParenListInitExpr>(Init);
+  const StringLiteral *SL = dyn_cast<StringLiteral>(Init);
   // If the initializer is an initializer list, first do the explicit elements.
-  if (ILE || CPLIE) {
+  if (ILE || CPLIE || SL) {
     // Initializing from a (braced) string literal is a special case; the init
     // list element does not initialize a (single) array element.
-    if (ILE && ILE->isStringLiteralInit()) {
+    if ((ILE && ILE->isStringLiteralInit()) || SL) {
       // Initialize the initial portion of length equal to that of the string
       // literal. The allocation must be for at least this much; we emitted a
       // check for that earlier.
@@ -1056,12 +1057,12 @@ void CodeGenFunction::EmitNewArrayInitializer(
                                 AggValueSlot::DoesNotOverlap,
                                 AggValueSlot::IsNotZeroed,
                                 AggValueSlot::IsSanitizerChecked);
-      EmitAggExpr(ILE->getInit(0), Slot);
+      EmitAggExpr(SL ? SL : ILE->getInit(0), Slot);
 
       // Move past these elements.
-      InitListElements =
-          cast<ConstantArrayType>(ILE->getType()->getAsArrayTypeUnsafe())
-              ->getSize().getZExtValue();
+      const ArrayType *AT = SL ? SL->getType()->getAsArrayTypeUnsafe()
+                               : ILE->getType()->getAsArrayTypeUnsafe();
+      InitListElements = cast<ConstantArrayType>(AT)->getSize().getZExtValue();
       CurPtr = Builder.CreateConstInBoundsGEP(
           CurPtr, InitListElements, "string.init.end");
 
@@ -1564,16 +1565,21 @@ llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) {
   // 1. Build a call to the allocation function.
   FunctionDecl *allocator = E->getOperatorNew();
 
-  // If there is a brace-initializer, cannot allocate fewer elements than inits.
+  // If there is a brace-initializer or C++20 parenthesized initializer, cannot
+  // allocate fewer elements than inits.
   unsigned minElements = 0;
   if (E->isArray() && E->hasInitializer()) {
-    const InitListExpr *ILE = dyn_cast<InitListExpr>(E->getInitializer());
-    if (ILE && ILE->isStringLiteralInit())
+    const Expr *Init = E->getInitializer();
+    const InitListExpr *ILE = dyn_cast<InitListExpr>(Init);
+    const CXXParenListInitExpr *CPLIE = dyn_cast<CXXParenListInitExpr>(Init);
+    if ((ILE && ILE->isStringLiteralInit()) || isa<StringLiteral>(Init)) {
       minElements =
-          cast<ConstantArrayType>(ILE->getType()->getAsArrayTypeUnsafe())
-              ->getSize().getZExtValue();
-    else if (ILE)
-      minElements = ILE->getNumInits();
+          cast<ConstantArrayType>(Init->getType()->getAsArrayTypeUnsafe())
+              ->getSize()
+              .getZExtValue();
+    } else if (ILE || CPLIE) {
+      minElements = ILE ? ILE->getNumInits() : CPLIE->getInitExprs().size();
+    }
   }
 
   llvm::Value *numElements = nullptr;
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 61d244f3bb9798..1fdebadb14e401 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -5495,14 +5495,12 @@ static void TryOrBuildParenListInitialization(
         return;
     }
     //   ...and value-initialized for each k < i <= n;
-    if (ArrayLength > Args.size()) {
-      InitializedEntity SubEntity = InitializedEntity::InitializeElement(
-          S.getASTContext(), Args.size(), Entity);
-      InitializationKind SubKind = InitializationKind::CreateValue(
-          Kind.getLocation(), Kind.getLocation(), Kind.getLocation(), true);
-      if (!HandleInitializedEntity(SubEntity, SubKind, nullptr, &ArrayFiller))
-        return;
-    }
+    InitializedEntity SubEntity = InitializedEntity::InitializeElement(
+        S.getASTContext(), Args.size(), Entity);
+    InitializationKind SubKind = InitializationKind::CreateValue(
+        Kind.getLocation(), Kind.getLocation(), Kind.getLocation(), true);
+    if (!HandleInitializedEntity(SubEntity, SubKind, nullptr, &ArrayFiller))
+      return;
 
     if (ResultType.isNull()) {
       ResultType = S.Context.getConstantArrayType(
diff --git a/clang/test/CodeGen/paren-list-agg-init.cpp b/clang/test/CodeGen/paren-list-agg-init.cpp
index 9618b6ddf14558..70b7bbfed0168d 100644
--- a/clang/test/CodeGen/paren-list-agg-init.cpp
+++ b/clang/test/CodeGen/paren-list-agg-init.cpp
@@ -531,22 +531,7 @@ namespace gh68198 {
 
   // CHECK: define {{.*}} void @{{.*foo26.*}} {
   // CHECK-NEXT: entry
-  // CHECK-NEXT: [[ARR_9:%.*arr9.*]] = alloca ptr, align 8
-  // CHECK-NEXT: [[CALL_PTR:%.*]] = call noalias noundef nonnull ptr @_Znam(i64 noundef 16) #7
-  // CHECK-NEXT: store i32 1, ptr [[CALL_PTR]], align 4
-  // CHECK-NEXT: [[ARRAY_EXP_NEXT:%.*]] = getelementptr inbounds i32, ptr [[CALL_PTR]], i64 1
-  // CHECK-NEXT: store i32 2, ptr [[ARRAY_EXP_NEXT]], align 4
-  // CHECK-NEXT: [[ARRAY_EXP_NEXT1:%.*]] = getelementptr inbounds i32, ptr [[ARRAY_EXP_NEXT]], i64 1
-  // CHECK-NEXT: call void @llvm.memset.p0.i64(ptr align 4 [[ARRAY_EXP_NEXT1]], i8 0, i64 8, i1 false)
-  // CHECK-NEXT: store ptr [[CALL_PTR]], ptr [[ARR_9]], align 8
-  // CHECK-NEXT: ret void
-  void foo26() {
-    int* arr9 = new int[4](1, 2);
-  }
-
-  // CHECK: define {{.*}} void @{{.*foo27.*}} {
-  // CHECK-NEXT: entry
-  // CHECK-NEXT: [[ARR_10:%.*arr10.*]] = alloca ptr, align 8
+  // CHECK-NEXT: [[ARR_10:%.*arr9.*]] = alloca ptr, align 8
   // CHECK-NEXT: [[CALL_PTR]] = call noalias noundef nonnull ptr @_Znam(i64 noundef 16)
   // CHECK-NEXT: [[ARRAYINIT_BEGIN:%.*]] = getelementptr inbounds [2 x i32], ptr [[CALL]], i64 0, i64 0
   // CHECK-NEXT: store i32 1, ptr [[ARRAYINIT_BEGIN]], align 4
@@ -560,13 +545,13 @@ namespace gh68198 {
   // CHECK-NEXT: [[ARRAY_EXP_NEXT3:%.*]] = getelementptr inbounds [2 x i32], ptr [[ARRAY_EXP_NEXT]], i64 1
   // CHECK-NEXT: store ptr [[CALL_PTR]], ptr [[ARR_10]], align 8
   // CHECK-NEXT: ret void
-  void foo27() {
-    void* arr10 = new int[][2]({1, 2}, {3, 4});
+  void foo26() {
+    void* arr9 = new int[][2]({1, 2}, {3, 4});
   }
 
-  // CHECK: define {{.*}} void @{{.*foo28.*}} {
+  // CHECK: define {{.*}} void @{{.*foo27.*}} {
   // CHECK-NEXT: entry
-  // CHECK-NEXT: [[ARR_11:%.*arr11.*]] = alloca ptr, align 8
+  // CHECK-NEXT: [[ARR_10:%.*arr10.*]] = alloca ptr, align 8
   // CHECK-NEXT: [[CALL_PTR]] = call noalias noundef nonnull ptr @_Znam(i64 noundef 32)
   // CHECK-NEXT: [[ARRAYINIT_BEGIN:%.*]] = getelementptr inbounds [2 x i32], ptr [[CALL]], i64 0, i64 0
   // CHECK-NEXT: store i32 5, ptr [[ARRAYINIT_BEGIN]], align 4
@@ -579,9 +564,9 @@ namespace gh68198 {
   // CHECK-NEXT: store i32 8, ptr [[ARRAYINIT_ELEMENT2]], align 4
   // CHECK-NEXT: [[ARRAY_EXP_NEXT3:%.*]] = getelementptr inbounds [2 x i32], ptr [[ARRAY_EXP_NEXT]], i64 1
   // CHECK-NEXT: call void @llvm.memset.p0.i64(ptr align 4 [[ARRAY_EXP_NEXT3]], i8 0, i64 16, i1 false)
-  // CHECK-NEXT: store ptr [[CALL_PTR]], ptr [[ARR_11]], align 8
+  // CHECK-NEXT: store ptr [[CALL_PTR]], ptr [[ARR_10]], align 8
   // CHECK-NEXT: ret void
-  void foo28() {
-    void* arr11 = new int[4][2]({5, 6}, {7, 8});
+  void foo27() {
+    void* arr10 = new int[4][2]({5, 6}, {7, 8});
   }
 }
diff --git a/clang/test/CodeGenCXX/new-array-init.cpp b/clang/test/CodeGenCXX/new-array-init.cpp
index db740d065e2f7e..6d80bd8035a7e9 100644
--- a/clang/test/CodeGenCXX/new-array-init.cpp
+++ b/clang/test/CodeGenCXX/new-array-init.cpp
@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -std=c++11 -triple i386-unknown-unknown %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -std=c++20 -triple i386-unknown-unknown %s -emit-llvm -o - | FileCheck %s --check-prefix=CHECK --check-prefix=CHECKCXX20
 // RUN: %clang_cc1 -std=c++11 -triple i386-unknown-unknown %s -emit-llvm -fsanitize=signed-integer-overflow -o - | FileCheck --check-prefix=SIO %s
 
 // CHECK: @[[ABC4:.*]] = {{.*}} constant [4 x i8] c"abc\00"
@@ -15,6 +16,19 @@ void fn(int n) {
   new int[n] { 1, 2, 3 };
 }
 
+#if __cplusplus >= 202002L
+// CHECKCXX20-LABEL: define{{.*}} void @_Z8fn_pareni
+void fn_paren(int n) {
+  // CHECKCXX20: icmp ult i{{32|64}} %{{[^ ]+}}, 3
+  // CHECKCXX20: store i32 1
+  // CHECKCXX20: store i32 2
+  // CHECKCXX20: store i32 3
+  // CHECKCXX20: sub {{.*}}, 12
+  // CHECKCXX20: call void @llvm.memset
+  new int[n](1, 2, 3);
+}
+#endif
+
 // CHECK-LABEL: define{{.*}} void @_Z11const_exactv
 void const_exact() {
   // CHECK-NOT: icmp ult i{{32|64}} %{{[^ ]+}}, 3
@@ -22,6 +36,15 @@ void const_exact() {
   new int[3] { 1, 2, 3 };
 }
 
+#if __cplusplus >= 202002L
+// CHECKCXX20-LABEL: define{{.*}} void @_Z17const_exact_parenv
+void const_exact_paren() {
+  // CHECKCXX20-NOT: icmp ult i{{32|64}} %{{[^ ]+}}, 3
+  // CHECKCXX20-NOT: icmp eq ptr
+  new int[3](1, 2, 3);
+}
+#endif
+
 // CHECK-LABEL: define{{.*}} void @_Z16const_sufficientv
 void const_sufficient() {
   // CHECK-NOT: icmp ult i{{32|64}} %{{[^ ]+}}, 3
@@ -29,6 +52,15 @@ void const_sufficient() {
   // CHECK: ret void
 }
 
+#if __cplusplus >= 202002L
+// CHECKCXX20-LABEL: define{{.*}} void @_Z22const_sufficient_parenv
+void const_sufficient_paren() {
+  // CHECKCXX20-NOT: icmp ult i{{32|64}} %{{[^ ]+}}, 3
+  new int[4](1, 2, 3);
+  // CHECKCXX20: ret void
+}
+#endif
+
 // CHECK-LABEL: define{{.*}} void @_Z22check_array_value_initv
 void check_array_value_init() {
   struct S;
@@ -46,7 +78,7 @@ void check_array_value_init() {
 
 // CHECK-LABEL: define{{.*}} void @_Z15string_nonconsti
 void string_nonconst(int n) {
-  // CHECK: icmp slt i{{32|64}} %{{[^ ]+}}, 4
+  // CHECK: icmp {{s|u}}lt i{{32|64}} %{{[^ ]+}}, 4
   // FIXME: Conditionally throw an exception rather than passing -1 to alloc function
   // CHECK: select
   // CHECK: %[[PTR:.*]] = call noalias noundef nonnull ptr @_Zna{{.}}(i{{32|64}}
@@ -57,6 +89,21 @@ void string_nonconst(int n) {
   new char[n] { "abc" };
 }
 
+#if __cplusplus >= 202002L
+// CHECKCXX20-LABEL: define{{.*}} void @_Z21string_nonconst_pareni
+void string_nonconst_paren(int n) {
+  // CHECKCXX20: icmp {{s|u}}lt i{{32|64}} %{{[^ ]+}}, 4
+  // FIXME: Conditionally throw an exception rather than passing -1 to alloc function
+  // CHECKCXX20: select
+  // CHECKCXX20: %[[PTR:.*]] = call noalias noundef nonnull ptr @_Zna{{.}}(i{{32|64}}
+  // CHECKCXX20: call void @llvm.memcpy{{.*}}(ptr align {{[0-9]+}} %[[PTR]], ptr align {{[0-9]+}} @[[ABC4]], i32 4,
+  // CHECKCXX20: %[[REST:.*]] = getelementptr inbounds i8, ptr %[[PTR]], i32 4
+  // CHECKCXX20: %[[RESTSIZE:.*]] = sub {{.*}}, 4
+  // CHECKCXX20: call void @llvm.memset{{.*}}(ptr align {{[0-9]+}} %[[REST]], i8 0, i{{32|64}} %[[RESTSIZE]],
+  new char[n]("abc");
+}
+#endif
+
 // CHECK-LABEL: define{{.*}} void @_Z12string_exactv
 void string_exact() {
   // CHECK-NOT: icmp
@@ -66,6 +113,17 @@ void string_exact() {
   new char[4] { "abc" };
 }
 
+#if __cplusplus >= 202002L
+// CHECKCXX20-LABEL: define{{.*}} void @_Z18string_exact_parenv
+void string_exact_paren() {
+  // CHECKCXX20-NOT: icmp
+  // CHECKCXX20: %[[PTR:.*]] = call noalias noundef nonnull ptr @_Zna{{.}}(i{{32|64}} noundef 4)
+  // CHECKCXX20: call void @llvm.memcpy{{.*}}(ptr align {{[0-9]+}} %[[PTR]], ptr align {{[0-9]+}} @[[ABC4]], i32 4,
+  // CHECKCXX20-NOT: memset
+  new char[4]("abc");
+}
+#endif
+
 // CHECK-LABEL: define{{.*}} void @_Z17string_sufficientv
 void string_sufficient() {
   // CHECK-NOT: icmp
@@ -76,6 +134,18 @@ void string_sufficient() {
   new char[15] { "abc" };
 }
 
+#if __cplusplus >= 202002L
+// CHECKCXX20-LABEL: define{{.*}} void @_Z23string_sufficient_parenv
+void string_sufficient_paren() {
+  // CHECKCXX20-NOT: icmp
+  // CHECKCXX20: %[[PTR:.*]] = call noalias noundef nonnull ptr @_Zna{{.}}(i{{32|64}} noundef 15)
+  // FIXME: For very large arrays, it would be preferable to emit a small copy and a memset.
+  // CHECKCXX20: call void @llvm.memcpy{{.*}}(ptr align {{[0-9]+}} %[[PTR]], ptr align {{[0-9]+}} @[[ABC15]], i32 15,
+  // CHECKCXX20-NOT: memset
+  new char[15] { "abc" };
+}
+#endif
+
 // CHECK-LABEL: define{{.*}} void @_Z10aggr_exactv
 void aggr_exact() {
   // CHECK-NOT: icmp
diff --git a/clang/test/SemaCXX/new-delete.cpp b/clang/test/SemaCXX/new-delete.cpp
index 2db32938f957fb..4f78b7c71a91c5 100644
--- a/clang/test/SemaCXX/new-delete.cpp
+++ b/clang/test/SemaCXX/new-delete.cpp
@@ -2,7 +2,7 @@
 // RUN: %clang_cc1 -fsyntax-only -verify=expected,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++11
 // RUN: %clang_cc1 -fsyntax-only -verify=expected,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++14
 // RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx17,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++17
-// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx17 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++20
+// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx17,cxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++20
 
 // FIXME Location is (frontend)
 // cxx17-note@*:* {{candidate function not viable: requires 2 arguments, but 3 were provided}}
@@ -27,6 +27,11 @@ struct U
 struct V : U
 {
 };
+struct W // cxx20-note 2{{candidate constructor}}
+{
+  int a;
+  int b;
+};
 
 inline void operator delete(void *); // expected-warning {{replacement function 'operator delete' cannot be declared 'inline'}}
 
@@ -359,6 +364,11 @@ void h(unsigned i) {
 template void h<unsigned>(unsigned);
 template void h<unsigned[10]>(unsigned); // precxx20-note {{in instantiation of function template specialization 'Test1::h<unsigned int[10]>' requested here}}
 
+void i() {
+  new W[2](1, 2, 3); // precxx20-error {{array 'new' cannot have initialization arguments}}
+  // cxx20-error at -1 {{no viable conversion from 'int' to 'W'}}
+}
+
 }
 
 // Don't diagnose access for overload candidates that aren't selected.

>From 8e308b22bbc97bea6085dccec3cbc653787b1799 Mon Sep 17 00:00:00 2001
From: Alan Zhao <ayzhao at google.com>
Date: Tue, 9 Jan 2024 17:26:33 -0800
Subject: [PATCH 6/6] only create array filler if it's a variable length array
 created with new

---
 clang/lib/Sema/SemaInit.cpp | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 1fdebadb14e401..0cc35d2b2e9911 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -5495,12 +5495,14 @@ static void TryOrBuildParenListInitialization(
         return;
     }
     //   ...and value-initialized for each k < i <= n;
-    InitializedEntity SubEntity = InitializedEntity::InitializeElement(
-        S.getASTContext(), Args.size(), Entity);
-    InitializationKind SubKind = InitializationKind::CreateValue(
-        Kind.getLocation(), Kind.getLocation(), Kind.getLocation(), true);
-    if (!HandleInitializedEntity(SubEntity, SubKind, nullptr, &ArrayFiller))
-      return;
+    if (ArrayLength > Args.size() || Entity.isVariableLengthArrayNew()) {
+      InitializedEntity SubEntity = InitializedEntity::InitializeElement(
+          S.getASTContext(), Args.size(), Entity);
+      InitializationKind SubKind = InitializationKind::CreateValue(
+          Kind.getLocation(), Kind.getLocation(), Kind.getLocation(), true);
+      if (!HandleInitializedEntity(SubEntity, SubKind, nullptr, &ArrayFiller))
+        return;
+    }
 
     if (ResultType.isNull()) {
       ResultType = S.Context.getConstantArrayType(



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