Revert "[ConstEval] Fix crash when comparing strings past the end"

[hnrklssn]

Reverts #137078

[llvmbot]

@llvm/pr-subscribers-clang

Author: Henrik G. Olsson (hnrklssn)

Changes

Reverts llvm/llvm-project#137078

---

Full diff: https://github.com/llvm/llvm-project/pull/137088.diff

3 Files Affected:

• (modified) clang/lib/AST/ExprConstant.cpp (+2-7)
• (modified) clang/test/AST/ByteCode/cxx20.cpp (-9)
• (modified) clang/test/SemaCXX/constant-expression-cxx11.cpp (-2)

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp index 7c933f47bf7f0..f598ef5929aa4 100644 --- a/clang/lib/AST/ExprConstant.cpp+++ b/clang/lib/AST/ExprConstant.cpp@@ -2232,15 +2232,10 @@ static bool ArePotentiallyOverlappingStringLiterals(const EvalInfo &Info, // within RHS. We don't need to look at the characters of one string that // would appear before the start of the other string if they were merged. CharUnits Offset = RHS.Offset - LHS.Offset; - if (Offset.isNegative()) {- if (LHSString.Bytes.size() < (size_t)-Offset.getQuantity())- return false;+ if (Offset.isNegative()) LHSString.Bytes = LHSString.Bytes.drop_front(-Offset.getQuantity()); - } else {- if (RHSString.Bytes.size() < (size_t)Offset.getQuantity())- return false;+ else RHSString.Bytes = RHSString.Bytes.drop_front(Offset.getQuantity()); - } bool LHSIsLonger = LHSString.Bytes.size() > RHSString.Bytes.size(); StringRef Longer = LHSIsLonger ? LHSString.Bytes : RHSString.Bytes; diff --git a/clang/test/AST/ByteCode/cxx20.cpp b/clang/test/AST/ByteCode/cxx20.cpp index 4c1b1592896c9..42e6ae33e92e4 100644 --- a/clang/test/AST/ByteCode/cxx20.cpp+++ b/clang/test/AST/ByteCode/cxx20.cpp@@ -119,15 +119,6 @@ constexpr auto b3 = name1() == name1(); // ref-error {{must be initialized by a constexpr auto b4 = name1() == name2(); static_assert(!b4); -constexpr auto bar(const char *p) { return p + __builtin_strlen(p); }-constexpr auto b5 = bar(p1) == p1;-static_assert(!b5);-constexpr auto b6 = bar(p1) == ""; // ref-error {{must be initialized by a constant expression}} \- // ref-note {{comparison of addresses of potentially overlapping literals}}-constexpr auto b7 = bar(p1) + 1 == ""; // both-error {{must be initialized by a constant expression}} \- // ref-note {{comparison against pointer '&"test1"[6]' that points past the end of a complete object has unspecified value}} \- // expected-note {{comparison against pointer '&"test1"[6] + 1' that points past the end of a complete object has unspecified value}}- namespace UninitializedFields { class A { public: diff --git a/clang/test/SemaCXX/constant-expression-cxx11.cpp b/clang/test/SemaCXX/constant-expression-cxx11.cpp index dc8f4bf1666ee..28016da925ef9 100644 --- a/clang/test/SemaCXX/constant-expression-cxx11.cpp+++ b/clang/test/SemaCXX/constant-expression-cxx11.cpp@@ -2203,8 +2203,6 @@ namespace BuiltinStrlen { static_assert(__builtin_strlen("foo") == 3, ""); static_assert(__builtin_strlen("foo\0quux") == 3, ""); static_assert(__builtin_strlen("foo\0quux" + 4) == 4, ""); - static_assert(__builtin_strlen("foo") + 1 + "foo" == "foo", ""); // expected-error {{static assertion expression is not an integral constant expression}}- // expected-note@-1 {{comparison against pointer '&"foo"[4]' that points past the end of a complete object has unspecified value}} constexpr bool check(const char *p) { return __builtin_strlen(p) == 3 &&