[clang] 95a0b4f - Revert "[clang][ExprConst] Allow comparisons with string literals (#106733)"

[Timm Bäder via cfe-commits]

Author: Timm Bäder
Date: 2024-09-17T05:58:54+02:00
New Revision: 95a0b4f729310d95d89f01f4d92ab7d2bf09941c

URL: https://github.com/llvm/llvm-project/commit/95a0b4f729310d95d89f01f4d92ab7d2bf09941c
DIFF: https://github.com/llvm/llvm-project/commit/95a0b4f729310d95d89f01f4d92ab7d2bf09941c.diff

LOG: Revert "[clang][ExprConst] Allow comparisons with string literals (#106733)"

This reverts commit 5d1d2f08c4a92580e7f6b3b6b77b2b6f6184e126.

See the discussion in https://github.com/llvm/llvm-project/pull/106733
and https://github.com/llvm/llvm-project/issues/58754

Added: 
    

Modified: 
    clang/lib/AST/ExprConstant.cpp
    clang/test/AST/ByteCode/cxx20.cpp
    clang/test/SemaCXX/constant-expression-cxx11.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 4af7752d3b238b..6387e375dda79c 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -2146,7 +2146,7 @@ static bool IsLiteralLValue(const LValue &Value) {
   if (Value.getLValueCallIndex())
     return false;
   const Expr *E = Value.Base.dyn_cast<const Expr*>();
-  return E && !isa<MaterializeTemporaryExpr, StringLiteral>(E);
+  return E && !isa<MaterializeTemporaryExpr>(E);
 }
 
 static bool IsWeakLValue(const LValue &Value) {

diff  --git a/clang/test/AST/ByteCode/cxx20.cpp b/clang/test/AST/ByteCode/cxx20.cpp
index b47a4b47d09644..9bbc3dbe0073d3 100644
--- a/clang/test/AST/ByteCode/cxx20.cpp
+++ b/clang/test/AST/ByteCode/cxx20.cpp
@@ -108,16 +108,22 @@ constexpr auto p2 = "test2";
 constexpr bool b1 = foo(p1) == foo(p1);
 static_assert(b1);
 
-constexpr bool b2 = foo(p1) == foo(p2);
-static_assert(!b2);
+constexpr bool b2 = foo(p1) == foo(p2); // ref-error {{must be initialized by a constant expression}} \
+                                        // ref-note {{comparison of addresses of literals}} \
+                                        // ref-note {{declared here}}
+static_assert(!b2); // ref-error {{not an integral constant expression}} \
+                    // ref-note {{not a constant expression}}
 
 constexpr auto name1() { return "name1"; }
 constexpr auto name2() { return "name2"; }
 
 constexpr auto b3 = name1() == name1();
 static_assert(b3);
-constexpr auto b4 = name1() == name2();
-static_assert(!b4);
+constexpr auto b4 = name1() == name2(); // ref-error {{must be initialized by a constant expression}} \
+                                        // ref-note {{has unspecified value}} \
+                                        // ref-note {{declared here}}
+static_assert(!b4); // ref-error {{not an integral constant expression}} \
+                    // ref-note {{not a constant expression}}
 
 namespace UninitializedFields {
   class A {

diff  --git a/clang/test/SemaCXX/constant-expression-cxx11.cpp b/clang/test/SemaCXX/constant-expression-cxx11.cpp
index d2d2f1a127eaeb..44ef540f41fa8c 100644
--- a/clang/test/SemaCXX/constant-expression-cxx11.cpp
+++ b/clang/test/SemaCXX/constant-expression-cxx11.cpp
@@ -358,9 +358,11 @@ struct Str {
 
 extern char externalvar[];
 constexpr bool constaddress = (void *)externalvar == (void *)0x4000UL; // expected-error {{must be initialized by a constant expression}} expected-note {{reinterpret_cast}}
-constexpr bool litaddress = "foo" == "foo"; // cxx20_23-warning {{comparison between two arrays is deprecated}}
+constexpr bool litaddress = "foo" == "foo"; // expected-error {{must be initialized by a constant expression}}
+// expected-note at -1 {{comparison of addresses of literals has unspecified value}}
+// cxx20_23-warning at -2 {{comparison between two arrays is deprecated}}
 static_assert(0 != "foo", "");
-static_assert("foo" != "foo", "");// cxx20_23-warning {{comparison between two arrays is deprecated}}
+
 }
 
 namespace MaterializeTemporary {