[PATCH] D149965: [clang][Interp] Fix tests for ignored expressions

[Timm Bäder via Phabricator via cfe-commits]

tbaeder updated this revision to Diff 520352.
tbaeder added a comment.

@aaron.ballman This is where the sizeof/alignof tests were actually broken.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D149965/new/

https://reviews.llvm.org/D149965

Files:
  clang/lib/AST/Interp/ByteCodeExprGen.cpp
  clang/test/AST/Interp/literals.cpp


Index: clang/test/AST/Interp/literals.cpp
===================================================================
--- clang/test/AST/Interp/literals.cpp
+++ clang/test/AST/Interp/literals.cpp
@@ -196,6 +196,21 @@
                                             // ref-error {{must be initialized by a constant expression}}
   }
 
+#if __cplusplus >= 201402L
+  constexpr int IgnoredRejected() { // ref-error {{never produces a constant expression}}
+    int n = 0;
+    sizeof(int[n++]); // expected-warning {{expression result unused}} \
+                      // ref-warning {{expression result unused}} \
+                      // ref-note 2{{subexpression not valid in a constant expression}}
+    return n;
+  }
+  /// FIXME: This is rejected because the parameter so sizeof() is not constant.
+  ///   produce a proper diagnostic.
+  static_assert(IgnoredRejected() == 0, ""); // expected-error {{not an integral constant expression}} \
+                                             // ref-error {{not an integral constant expression}} \
+                                             // ref-note {{in call to 'IgnoredRejected()'}}
+#endif
+
 
 #if __cplusplus >= 202002L
   /// FIXME: The following code should be accepted.
@@ -886,7 +901,7 @@
   struct A{ int a; };
   constexpr int ignoredExprs() {
     (void)(1 / 2);
-    A a;
+    A a{12};
     a;
     (void)a;
     (a);
@@ -902,9 +917,12 @@
     arr[0];
     "a";
     'b';
+    sizeof(int);
+    alignof(int);
 
     return 0;
   }
+  static_assert(ignoredExprs() == 0, "");
 
   constexpr int oh_my(int x) {
     (int){ x++ };
Index: clang/lib/AST/Interp/ByteCodeExprGen.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -200,6 +200,8 @@
   case CK_NoOp:
   case CK_UserDefinedConversion:
   case CK_BitCast:
+    if (DiscardResult)
+      return this->discard(SubExpr);
     return this->visit(SubExpr);
 
   case CK_IntegralToBoolean:
@@ -588,6 +590,9 @@
       Size = ASTCtx.getTypeSizeInChars(ArgType);
     }
 
+    if (DiscardResult)
+      return true;
+
     return this->emitConst(Size.getQuantity(), E);
   }
 
@@ -618,6 +623,9 @@
         Size = AlignOfType(Arg->getType(), ASTCtx, Kind);
     }
 
+    if (DiscardResult)
+      return true;
+
     return this->emitConst(Size.getQuantity(), E);
   }
 


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