[PATCH] D148981: [clang][Interp] PointerToBoolean casts

[Timm Bäder via Phabricator via cfe-commits]

tbaeder created this revision.
tbaeder added reviewers: aaron.ballman, erichkeane, tahonermann, shafik.
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tbaeder requested review of this revision.
Herald added a project: clang.
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Just emit `p != nullptr` for this.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D148981

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
@@ -106,6 +106,19 @@
 }
 static_assert(gimme(5) == 5, "");
 
+namespace PointerToBool {
+
+  constexpr void *N = nullptr;
+  constexpr bool B = N;
+  static_assert(!B, "");
+  static_assert(!N, "");
+
+  constexpr float F = 1.0;
+  constexpr const float *FP = &F;
+  static_assert(FP, "");
+  static_assert(!!FP, "");
+}
+
 namespace SizeOf {
   constexpr int soint = sizeof(int);
   constexpr int souint = sizeof(unsigned int);
Index: clang/lib/AST/Interp/ByteCodeExprGen.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -204,6 +204,17 @@
     return this->emitCast(*FromT, *ToT, CE);
   }
 
+  case CK_PointerToBoolean: {
+    // Just emit p != nullptr for this.
+    if (!this->visit(SubExpr))
+      return false;
+
+    if (!this->emitNullPtr(CE))
+      return false;
+
+    return this->emitNEPtr(CE);
+  }
+
   case CK_ToVoid:
     return discard(SubExpr);
 


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