https://github.com/tbaederr created
https://github.com/llvm/llvm-project/pull/130485
When such a pointer is heap allocated, the type we get is a pointer type. Take
the pointee type in that case.
>From eb19b865be45021df556d5dfa247abfb6e129e76 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbae...@redhat.com>
Date: Sun, 9 Mar 2025 12:30:04 +0100
Subject: [PATCH] [clang][bytecode] Fix getting pointer element type in
__builtin_memcmp
When such a pointer is heap allocated, the type we get is a pointer
type. Take the pointee type in that case.
---
clang/lib/AST/ByteCode/InterpBuiltin.cpp | 14 ++++++++++++--
clang/test/AST/ByteCode/builtin-functions.cpp | 15 +++++++++++++++
2 files changed, 27 insertions(+), 2 deletions(-)
diff --git a/clang/lib/AST/ByteCode/InterpBuiltin.cpp
b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
index b8c4ef2f48a79..70c7fe5b714cb 100644
--- a/clang/lib/AST/ByteCode/InterpBuiltin.cpp
+++ b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
@@ -1881,11 +1881,21 @@ static bool interp__builtin_memcmp(InterpState &S,
CodePtr OpPC,
bool IsWide =
(ID == Builtin::BIwmemcmp || ID == Builtin::BI__builtin_wmemcmp);
+ auto getElemType = [](const Pointer &P) -> QualType {
+ const Descriptor *Desc = P.getFieldDesc();
+ QualType T = Desc->getType();
+ if (T->isPointerType())
+ return T->getAs<PointerType>()->getPointeeType();
+ if (Desc->isArray())
+ return Desc->getElemQualType();
+ return T;
+ };
+
const ASTContext &ASTCtx = S.getASTContext();
// FIXME: This is an arbitrary limitation the current constant interpreter
// had. We could remove this.
- if (!IsWide && (!isOneByteCharacterType(PtrA.getType()) ||
- !isOneByteCharacterType(PtrB.getType()))) {
+ if (!IsWide && (!isOneByteCharacterType(getElemType(PtrA)) ||
+ !isOneByteCharacterType(getElemType(PtrB)))) {
S.FFDiag(S.Current->getSource(OpPC),
diag::note_constexpr_memcmp_unsupported)
<< ASTCtx.BuiltinInfo.getQuotedName(ID) << PtrA.getType()
diff --git a/clang/test/AST/ByteCode/builtin-functions.cpp
b/clang/test/AST/ByteCode/builtin-functions.cpp
index dbff9164a91c1..29812553af9f0 100644
--- a/clang/test/AST/ByteCode/builtin-functions.cpp
+++ b/clang/test/AST/ByteCode/builtin-functions.cpp
@@ -1352,6 +1352,21 @@ namespace Memcmp {
static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 7) == -1);
static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 6) == -1);
static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 5) == 0);
+
+#if __cplusplus >= 202002L
+ constexpr bool f() {
+ char *c = new char[12];
+ c[0] = 'b';
+
+ char n = 'a';
+ bool b = __builtin_memcmp(c, &n, 1) == 0;
+
+ delete[] c;
+ return !b;
+ }
+ static_assert(f());
+#endif
+
}
namespace Memchr {
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