[PATCH] D151587: [clang][ConstantEmitter] have tryEmitPrivateForVarInit try ConstExprEmitter fast-path first

[Nick Desaulniers via Phabricator via cfe-commits]

nickdesaulniers updated this revision to Diff 527978.
nickdesaulniers marked an inline comment as done.
nickdesaulniers added a comment.

- remove unnecessary Visit*CastExpr overrides


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D151587/new/

https://reviews.llvm.org/D151587

Files:
  clang/lib/CodeGen/CGExprConstant.cpp
  clang/test/CodeGenCXX/const-init-cxx11.cpp
  clang/test/CodeGenCXX/const-init-cxx1y.cpp
  clang/test/CodeGenOpenCL/amdgpu-nullptr.cl


Index: clang/test/CodeGenOpenCL/amdgpu-nullptr.cl
===================================================================
--- clang/test/CodeGenOpenCL/amdgpu-nullptr.cl
+++ clang/test/CodeGenOpenCL/amdgpu-nullptr.cl
@@ -57,7 +57,7 @@
 // CHECK: @fold_generic ={{.*}} local_unnamed_addr addrspace(1) global ptr null, align 8
 generic int *fold_generic = (global int*)(generic float*)(private char*)0;
 
-// CHECK: @fold_priv ={{.*}} local_unnamed_addr addrspace(1) global ptr addrspace(5) addrspacecast (ptr null to ptr addrspace(5)), align 4
+// CHECK: @fold_priv ={{.*}} local_unnamed_addr addrspace(1) global ptr addrspace(5) addrspacecast (ptr addrspace(1) null to ptr addrspace(5)), align 4
 private short *fold_priv = (private short*)(generic int*)(global void*)0;
 
 // CHECK: @fold_priv_arith ={{.*}} local_unnamed_addr addrspace(1) global ptr addrspace(5) inttoptr (i32 9 to ptr addrspace(5)), align 4
Index: clang/test/CodeGenCXX/const-init-cxx1y.cpp
===================================================================
--- clang/test/CodeGenCXX/const-init-cxx1y.cpp
+++ clang/test/CodeGenCXX/const-init-cxx1y.cpp
@@ -34,8 +34,8 @@
   // 'c.temporary', not the value as modified by the partial evaluation within
   // the initialization of 'c.x'.
   A c = { 10, (++c.temporary, b.x) };
-  // CHECK: @_ZGRN21ModifyStaticTemporary1cE_ = internal global i32 10
   // CHECK: @_ZN21ModifyStaticTemporary1cE ={{.*}} global {{.*}} zeroinitializer
+  // CHECK: @_ZGRN21ModifyStaticTemporary1cE_ = internal global i32 10
 }
 
 // CHECK: @_ZGRN28VariableTemplateWithConstRef1iIvEE_ = linkonce_odr constant i32 5, align 4
Index: clang/test/CodeGenCXX/const-init-cxx11.cpp
===================================================================
--- clang/test/CodeGenCXX/const-init-cxx11.cpp
+++ clang/test/CodeGenCXX/const-init-cxx11.cpp
@@ -88,7 +88,7 @@
 
   struct E {};
   struct Test2 : X<E,0>, X<E,1>, X<E,2>, X<E,3> {};
-  // CHECK: @_ZN9BaseClass2t2E ={{.*}} constant {{.*}} undef
+  // CHECK: @_ZN9BaseClass2t2E ={{.*}} constant {{.*}} zeroinitializer, align 1
   extern constexpr Test2 t2 = Test2();
 
   struct __attribute((packed)) PackedD { double y = 2; };
Index: clang/lib/CodeGen/CGExprConstant.cpp
===================================================================
--- clang/lib/CodeGen/CGExprConstant.cpp
+++ clang/lib/CodeGen/CGExprConstant.cpp
@@ -1216,8 +1216,10 @@
   }
 
   llvm::Constant *VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E,
-                                                QualType T) {
-    return Visit(E->getSubExpr(), T);
+                                              QualType T) {
+    if (E->isLValue() || E->isXValue())
+      return Visit(E->getSubExpr(), T);
+    return nullptr;
   }
 
   llvm::Constant *EmitArrayInitialization(InitListExpr *ILE, QualType T) {
@@ -1276,6 +1278,9 @@
   }
 
   llvm::Constant *VisitInitListExpr(InitListExpr *ILE, QualType T) {
+    if (ILE->getNumInits() && isa<MaterializeTemporaryExpr>(ILE->getInit(0)))
+        return nullptr;
+
     if (ILE->isTransparent())
       return Visit(ILE->getInit(0), T);
 
@@ -1655,27 +1660,27 @@
 
   QualType destType = D.getType();
 
-  // Try to emit the initializer.  Note that this can allow some things that
-  // are not allowed by tryEmitPrivateForMemory alone.
-  if (APValue *value = D.evaluateValue())
-    return tryEmitPrivateForMemory(*value, destType);
-
   // FIXME: Implement C++11 [basic.start.init]p2: if the initializer of a
   // reference is a constant expression, and the reference binds to a temporary,
   // then constant initialization is performed. ConstExprEmitter will
   // incorrectly emit a prvalue constant in this case, and the calling code
   // interprets that as the (pointer) value of the reference, rather than the
   // desired value of the referee.
-  if (destType->isReferenceType())
-    return nullptr;
 
   const Expr *E = D.getInit();
   assert(E && "No initializer to emit");
 
   QualType nonMemoryDestType = getNonMemoryType(CGM, destType);
-  if (llvm::Constant *C = ConstExprEmitter(*this).Visit(const_cast<Expr *>(E),
-                                                        nonMemoryDestType))
-    return emitForMemory(C, destType);
+  if (!destType->isReferenceType())
+    if (llvm::Constant *C = ConstExprEmitter(*this).Visit(const_cast<Expr *>(E),
+                                                          nonMemoryDestType))
+      return emitForMemory(C, destType);
+
+  // Try to emit the initializer.  Note that this can allow some things that
+  // are not allowed by tryEmitPrivateForMemory alone.
+  if (APValue *value = D.evaluateValue())
+    return tryEmitPrivateForMemory(*value, destType);
+
   return nullptr;
 }
 

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