[PATCH] D72242: Fix crash on value dependent bitfields in if conditions in templates

[Elizabeth Andrews via Phabricator via cfe-commits]

eandrews created this revision.
eandrews added reviewers: rnk, erichkeane, alexfh, alexfh_.

This patch is a follow up to D69950 <https://reviews.llvm.org/D69950>, to fix a 
new crash on CXX condition expressions in templates, for value dependent 
bitfields.  Clang currently crashes when integral promotion is attempted on the 
condition. This patch adds a guard to prevent the promotion for value dependent 
bitfields. Prior to D69950 <https://reviews.llvm.org/D69950>, the guard was 
unnecessary because incorrect type dependency of bitfield prevented the 
compiler from reaching this code.


https://reviews.llvm.org/D72242

Files:
  clang/lib/Sema/SemaOverload.cpp
  clang/test/SemaTemplate/value-dependent-bitfield-cond.cpp


Index: clang/test/SemaTemplate/value-dependent-bitfield-cond.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaTemplate/value-dependent-bitfield-cond.cpp
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+template<int b>
+class a {
+  int c : b;
+  void f() {
+    if (c)
+      ;
+  }
+};
+
Index: clang/lib/Sema/SemaOverload.cpp
===================================================================
--- clang/lib/Sema/SemaOverload.cpp
+++ clang/lib/Sema/SemaOverload.cpp
@@ -2158,6 +2158,7 @@
     if (FieldDecl *MemberDecl = From->getSourceBitField()) {
       llvm::APSInt BitWidth;
       if (FromType->isIntegralType(Context) &&
+          !MemberDecl->getBitWidth()->isValueDependent() &&
           MemberDecl->getBitWidth()->isIntegerConstantExpr(BitWidth, Context)) 
{
         llvm::APSInt ToSize(BitWidth.getBitWidth(), BitWidth.isUnsigned());
         ToSize = Context.getTypeSize(ToType);



Index: clang/test/SemaTemplate/value-dependent-bitfield-cond.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaTemplate/value-dependent-bitfield-cond.cpp
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+template<int b>
+class a {
+  int c : b;
+  void f() {
+    if (c)
+      ;
+  }
+};
+
Index: clang/lib/Sema/SemaOverload.cpp
===================================================================
--- clang/lib/Sema/SemaOverload.cpp
+++ clang/lib/Sema/SemaOverload.cpp
@@ -2158,6 +2158,7 @@
     if (FieldDecl *MemberDecl = From->getSourceBitField()) {
       llvm::APSInt BitWidth;
       if (FromType->isIntegralType(Context) &&
+          !MemberDecl->getBitWidth()->isValueDependent() &&
           MemberDecl->getBitWidth()->isIntegerConstantExpr(BitWidth, Context)) {
         llvm::APSInt ToSize(BitWidth.getBitWidth(), BitWidth.isUnsigned());
         ToSize = Context.getTypeSize(ToType);

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