From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Tue, 19 Jun 2012 21:28:35 +0000 (+0000)
Subject: Fix -Wc++11-narrowing warnings for narrowing negative values to larger unsigned
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=5d7700ed7645698f3e5bea8f983e61a1ec2f423b;p=clang

Fix -Wc++11-narrowing warnings for narrowing negative values to larger unsigned
types to actually includes the value, rather than saying <uninitialized>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@158745 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaOverload.cpp b/lib/Sema/SemaOverload.cpp
index 9167650ef9..013af8a8f6 100644
--- a/lib/Sema/SemaOverload.cpp
+++ b/lib/Sema/SemaOverload.cpp
@@ -397,14 +397,14 @@ StandardConversionSequence::getNarrowingKind(ASTContext &Ctx,
       if (!Initializer->isIntegerConstantExpr(InitializerValue, Ctx)) {
         // Such conversions on variables are always narrowing.
         return NK_Variable_Narrowing;
-      } else if (FromWidth < ToWidth) {
+      }
+      bool Narrowing = false;
+      if (FromWidth < ToWidth) {
         // Negative -> unsigned is narrowing. Otherwise, more bits is never
         // narrowing.
         if (InitializerValue.isSigned() && InitializerValue.isNegative())
-          return NK_Constant_Narrowing;
+          Narrowing = true;
       } else {
-        ConstantValue = APValue(InitializerValue);
-
         // Add a bit to the InitializerValue so we don't have to worry about
         // signed vs. unsigned comparisons.
         InitializerValue = InitializerValue.extend(
@@ -416,10 +416,13 @@ StandardConversionSequence::getNarrowingKind(ASTContext &Ctx,
         ConvertedValue = ConvertedValue.extend(InitializerValue.getBitWidth());
         ConvertedValue.setIsSigned(InitializerValue.isSigned());
         // If the result is different, this was a narrowing conversion.
-        if (ConvertedValue != InitializerValue) {
-          ConstantType = Initializer->getType();
-          return NK_Constant_Narrowing;
-        }
+        if (ConvertedValue != InitializerValue)
+          Narrowing = true;
+      }
+      if (Narrowing) {
+        ConstantType = Initializer->getType();
+        ConstantValue = APValue(InitializerValue);
+        return NK_Constant_Narrowing;
       }
     }
     return NK_Not_Narrowing;
diff --git a/test/CXX/dcl.decl/dcl.init/dcl.init.list/p7-0x.cpp b/test/CXX/dcl.decl/dcl.init/dcl.init.list/p7-0x.cpp
index e3909cce13..9b1727fd04 100644
--- a/test/CXX/dcl.decl/dcl.init/dcl.init.list/p7-0x.cpp
+++ b/test/CXX/dcl.decl/dcl.init/dcl.init.list/p7-0x.cpp
@@ -169,18 +169,18 @@ void shrink_int() {
   Agg<char> ce2 = { ConvertVar<short>() }; // expected-error {{non-constant-expression cannot be narrowed from type 'short' to 'char'}} expected-note {{override}}
 
   // Negative -> larger unsigned type.
-  unsigned long long ll1 = { -1 }; // expected-error {{cannot be narrowed}} expected-note {{override}}
+  unsigned long long ll1 = { -1 }; // expected-error {{ -1 which cannot be narrowed}} expected-note {{override}}
   unsigned long long ll2 = { 1 }; // OK
-  unsigned long long ll3 = { s }; // expected-error {{cannot be narrowed}} expected-note {{override}}
+  unsigned long long ll3 = { s }; // expected-error {{cannot be narrowed from type 'short'}} expected-note {{override}}
   unsigned long long ll4 = { us }; // OK
-  unsigned long long ll5 = { ll }; // expected-error {{cannot be narrowed}} expected-note {{override}}
-  Agg<unsigned long long> ll6 = { -1 }; // expected-error {{cannot be narrowed}} expected-note {{override}}
+  unsigned long long ll5 = { ll }; // expected-error {{cannot be narrowed from type 'long long'}} expected-note {{override}}
+  Agg<unsigned long long> ll6 = { -1 }; // expected-error {{ -1 which cannot be narrowed}} expected-note {{override}}
   Agg<unsigned long long> ll7 = { 18446744073709551615ULL }; // OK
-  Agg<unsigned long long> ll8 = { __int128(18446744073709551615ULL) + 1 }; // expected-error {{cannot be narrowed}} expected-note {{override}} expected-warning {{changes value}}
+  Agg<unsigned long long> ll8 = { __int128(18446744073709551615ULL) + 1 }; // expected-error {{ 18446744073709551616 which cannot be narrowed}} expected-note {{override}} expected-warning {{changes value}}
   signed char c = 'x';
-  unsigned short usc1 = { c }; // expected-error {{cannot be narrowed}} expected-note {{override}}
+  unsigned short usc1 = { c }; // expected-error {{non-constant-expression cannot be narrowed from type 'signed char'}} expected-note {{override}}
   unsigned short usc2 = { (signed char)'x' }; // OK
-  unsigned short usc3 = { (signed char)-1 }; // expected-error {{cannot be narrowed}} expected-note {{override}}
+  unsigned short usc3 = { (signed char)-1 }; // expected-error {{ -1 which cannot be narrowed}} expected-note {{override}}
 }
 
 // Be sure that type- and value-dependent expressions in templates get the error