https://github.com/spall created https://github.com/llvm/llvm-project/pull/160355
Enable InitList code to handle zero sized structs; this includes structs with no fields and those with only unnamed bitfields. Closes #157920 >From 40676e4d17e9d56395f5f4ea0804b409fde6fbb7 Mon Sep 17 00:00:00 2001 From: Sarah Spall <[email protected]> Date: Tue, 23 Sep 2025 11:16:26 -0700 Subject: [PATCH] ok to init struct with zero members --- clang/lib/Sema/SemaHLSL.cpp | 2 + .../CodeGenHLSL/BasicFeatures/InitLists.hlsl | 42 +++++++++++++++++++ 2 files changed, 44 insertions(+) diff --git a/clang/lib/Sema/SemaHLSL.cpp b/clang/lib/Sema/SemaHLSL.cpp index 7a61474e2a25c..7f85886f72366 100644 --- a/clang/lib/Sema/SemaHLSL.cpp +++ b/clang/lib/Sema/SemaHLSL.cpp @@ -4284,6 +4284,8 @@ bool SemaHLSL::transformInitList(const InitializedEntity &Entity, } size_t ExpectedSize = ILT.DestTypes.size(); size_t ActualSize = ILT.ArgExprs.size(); + if (ExpectedSize == 0 && ActualSize == 0) + return true; // For incomplete arrays it is completely arbitrary to choose whether we think // the user intended fewer or more elements. This implementation assumes that // the user intended more, and errors that there are too few initializers to diff --git a/clang/test/CodeGenHLSL/BasicFeatures/InitLists.hlsl b/clang/test/CodeGenHLSL/BasicFeatures/InitLists.hlsl index 5a5c45f686956..5fe69806b61eb 100644 --- a/clang/test/CodeGenHLSL/BasicFeatures/InitLists.hlsl +++ b/clang/test/CodeGenHLSL/BasicFeatures/InitLists.hlsl @@ -50,6 +50,16 @@ struct Unnamed { int : 8; }; +struct Empty { +}; + +struct UnnamedOnly { + int : 8; +}; + +// CHECK-DAG: [[ConstE:@.*]] = private unnamed_addr constant %struct.Empty undef, align 1 +// CHECK-DAG: [[ConstUO:@.*]] = private unnamed_addr constant %struct.UnnamedOnly undef, align 1 + // Case 1: Extraneous braces get ignored in literal instantiation. // CHECK-LABEL: define hidden void @_Z5case1v( // CHECK-SAME: ptr dead_on_unwind noalias writable sret([[STRUCT_TWOFLOATS:%.*]]) align 1 [[AGG_RESULT:%.*]]) #[[ATTR0:[0-9]+]] { @@ -985,3 +995,35 @@ void case18() { void case19(Unnamed U) { TwoInts TI = {U, 1}; } + +// InitList with Empty Struct on LHS +// CHECK-LABEL: case20 +// CHECK: [[E:%.*]] = alloca %struct.Empty, align 1 +// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 1 [[E]], ptr align 1 [[ConstE]], i32 1, i1 false) +void case20() { + Empty E = {}; +} + +// InitList with Empty Struct on RHS +// CHECK-LABEL: case21 +// CHECK: [[TI:%.*]] = alloca %struct.TwoInts, align 1 +// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 1 %TI, ptr align 1 {{.*}}, i32 8, i1 false) +void case21(Empty E) { + TwoInts TI = {E, 1, 2}; +} + +// InitList with Struct with only unnamed bitfield on LHS +// CHECK-LABEL: case22 +// CHECK: [[UO:%.*]] = alloca %struct.UnnamedOnly, align 1 +// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 1 [[UO]], ptr align 1 [[ConstUO]], i32 1, i1 false) +void case22() { + UnnamedOnly UO = {}; +} + +// InitList with Struct with only unnamed bitfield on RHS +// CHECK-LABEL: case23 +// CHECK: [[TI:%.*]] = alloca %struct.TwoInts, align 1 +// CHECK-NEXT: call void @llvm.memcpy.p0.p0.i32(ptr align 1 [[TI]], ptr align 1 {{.*}}, i32 8, i1 false) +void case23(UnnamedOnly UO) { + TwoInts TI = {UO, 1, 2}; +} _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
