[clang] 6aac11b - [clang][Interp] Evaluate Base when discarding a MemberExpr
Timm Bäder via cfe-commits
cfe-commits at lists.llvm.org
Tue Aug 1 01:16:49 PDT 2023
Author: Timm Bäder
Date: 2023-08-01T10:16:31+02:00
New Revision: 6aac11bad9763dd0ff14637823311187fc3c11a7
URL: https://github.com/llvm/llvm-project/commit/6aac11bad9763dd0ff14637823311187fc3c11a7
DIFF: https://github.com/llvm/llvm-project/commit/6aac11bad9763dd0ff14637823311187fc3c11a7.diff
LOG: [clang][Interp] Evaluate Base when discarding a MemberExpr
The Base expression might cause side-effects, so we still have to
evaluate it.
Differential Revision: https://reviews.llvm.org/D149828
Added:
Modified:
clang/lib/AST/Interp/ByteCodeExprGen.cpp
clang/test/AST/Interp/literals.cpp
Removed:
################################################################################
diff --git a/clang/lib/AST/Interp/ByteCodeExprGen.cpp b/clang/lib/AST/Interp/ByteCodeExprGen.cpp
index fcdfe19bd84439..39dd42655436da 100644
--- a/clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ b/clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -562,18 +562,18 @@ bool ByteCodeExprGen<Emitter>::VisitUnaryExprOrTypeTraitExpr(
template <class Emitter>
bool ByteCodeExprGen<Emitter>::VisitMemberExpr(const MemberExpr *E) {
- if (DiscardResult)
- return true;
-
// 'Base.Member'
const Expr *Base = E->getBase();
- const ValueDecl *Member = E->getMemberDecl();
+
+ if (DiscardResult)
+ return this->discard(Base);
if (!this->visit(Base))
return false;
// Base above gives us a pointer on the stack.
// TODO: Implement non-FieldDecl members.
+ const ValueDecl *Member = E->getMemberDecl();
if (const auto *FD = dyn_cast<FieldDecl>(Member)) {
const RecordDecl *RD = FD->getParent();
const Record *R = getRecord(RD);
diff --git a/clang/test/AST/Interp/literals.cpp b/clang/test/AST/Interp/literals.cpp
index 505ab8fc764f14..6610770a884e21 100644
--- a/clang/test/AST/Interp/literals.cpp
+++ b/clang/test/AST/Interp/literals.cpp
@@ -876,7 +876,7 @@ constexpr int ignoredDecls() {
}
static_assert(ignoredDecls() == 12, "");
-struct A{};
+struct A{ int a; };
constexpr int ignoredExprs() {
(void)(1 / 2);
A a;
@@ -908,6 +908,19 @@ constexpr int Comma(int start) {
constexpr int Value = Comma(5);
static_assert(Value == 8, "");
+/// Ignored MemberExprs need to still evaluate the Base
+/// expr.
+constexpr A callme(int &i) {
+ ++i;
+ return A{};
+}
+constexpr int ignoredMemberExpr() {
+ int i = 0;
+ callme(i).a; // ref-warning {{result unused}} \
+ // expected-warning {{result unused}}
+ return i;
+}
+static_assert(ignoredMemberExpr() == 1, "");
#endif
namespace PredefinedExprs {
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