Split out -Wconversion warnings about constant precision into their

own subcategory, -Wconstant-conversion, which is on by default.

Tweak the constant folder to give better results in the invalid
case of a negative shift amount.

Implements rdar://problem/6792488

llvm-svn: 118636

4 files changed, 32 insertions, 23 deletions

diff --git a/clang/test/Lexer/constants.c b/clang/test/Lexer/constants.c
index de0962e97d2..3d2da2c764e 100644
--- a/clang/test/Lexer/constants.c
+++ b/clang/test/Lexer/constants.c
@@ -15,7 +15,7 @@ float Y = 08.123456;
 #endif
 
 
-char c[] = {
+int c[] = {
   'df',   // expected-warning {{multi-character character constant}}
   '\t',
   '\\
@@ -34,12 +34,12 @@ int m3 = '\\\
 
 #pragma clang diagnostic ignored "-Wmultichar"
 
-char d = 'df'; // no warning.
-char e = 'abcd';  // still warn: expected-warning {{multi-character character constant}}
+int d = 'df'; // no warning.
+int e = 'abcd';  // still warn: expected-warning {{multi-character character constant}}
 
 #pragma clang diagnostic ignored "-Wfour-char-constants"
 
-char f = 'abcd';  // ignored.
+int f = 'abcd';  // ignored.
 
 // rdar://problem/6974641
 float t0[] = {
diff --git a/clang/test/Preprocessor/pushable-diagnostics.c b/clang/test/Preprocessor/pushable-diagnostics.c
index 567a866fa33..877eaaa0b36 100644
--- a/clang/test/Preprocessor/pushable-diagnostics.c
+++ b/clang/test/Preprocessor/pushable-diagnostics.c
@@ -4,14 +4,14 @@
 
 #pragma clang diagnostic puhs // expected-warning {{pragma diagnostic expected 'error', 'warning', 'ignored', 'fatal', 'push', or 'pop'}}
 
-char a = 'df'; // expected-warning{{multi-character character constant}}
+int a = 'df'; // expected-warning{{multi-character character constant}}
 
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wmultichar"
 
-char b = 'df'; // no warning.
+int b = 'df'; // no warning.
 #pragma clang diagnostic pop
 
-char c = 'df';  // expected-warning{{multi-character character constant}}
+int c = 'df';  // expected-warning{{multi-character character constant}}
 
 #pragma clang diagnostic pop // expected-warning{{pragma diagnostic pop could not pop, no matching push}}
diff --git a/clang/test/Sema/constant-conversion.c b/clang/test/Sema/constant-conversion.c
new file mode 100644
index 00000000000..cacd5968dc0
--- /dev/null
+++ b/clang/test/Sema/constant-conversion.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -triple x86_64-apple-darwin %s
+
+// This file tests -Wconstant-conversion, a subcategory of -Wconversion
+// which is on by default.
+
+// rdar://problem/6792488
+void test_6792488(void) {
+  int x = 0x3ff0000000000000U; // expected-warning {{implicit conversion from 'unsigned long' to 'int' changes value from 4607182418800017408 to 0}}
+}
diff --git a/clang/test/Sema/conversion.c b/clang/test/Sema/conversion.c
index 411ca32b5a6..e78902332eb 100644
--- a/clang/test/Sema/conversion.c
+++ b/clang/test/Sema/conversion.c
@@ -40,17 +40,17 @@ void test0(char c, short s, int i, long l, long long ll) {
   l = (long) 0;
 
   c = (char) BIG;
-  c = (short) BIG; // expected-warning {{implicit conversion loses integer precision}}
-  c = (int) BIG; // expected-warning {{implicit conversion loses integer precision}}
-  c = (long) BIG; // expected-warning {{implicit conversion loses integer precision}}
+  c = (short) BIG; // expected-warning {{implicit conversion from 'short' to 'char' changes value}}
+  c = (int) BIG; // expected-warning {{implicit conversion from 'int' to 'char' changes value}}
+  c = (long) BIG; // expected-warning {{implicit conversion from 'long' to 'char' changes value}}
   s = (char) BIG;
   s = (short) BIG;
-  s = (int) BIG; // expected-warning {{implicit conversion loses integer precision}}
-  s = (long) BIG; // expected-warning {{implicit conversion loses integer precision}}
+  s = (int) BIG; // expected-warning {{implicit conversion from 'int' to 'short' changes value}}
+  s = (long) BIG; // expected-warning {{implicit conversion from 'long' to 'short' changes value}}
   i = (char) BIG;
   i = (short) BIG;
   i = (int) BIG;
-  i = (long) BIG; // expected-warning {{implicit conversion loses integer precision}}
+  i = (long) BIG; // expected-warning {{implicit conversion from 'long' to 'int' changes value}}
   l = (char) BIG;
   l = (short) BIG;
   l = (int) BIG;
@@ -63,10 +63,10 @@ char test1(long long ll) {
   return (int) ll; // expected-warning {{implicit conversion loses integer precision}}
   return (short) ll; // expected-warning {{implicit conversion loses integer precision}}
   return (char) ll;
-  return (long long) BIG; // expected-warning {{implicit conversion loses integer precision}}
-  return (long) BIG; // expected-warning {{implicit conversion loses integer precision}}
-  return (int) BIG; // expected-warning {{implicit conversion loses integer precision}}
-  return (short) BIG; // expected-warning {{implicit conversion loses integer precision}}
+  return (long long) BIG; // expected-warning {{implicit conversion from 'long long' to 'char' changes value}}
+  return (long) BIG; // expected-warning {{implicit conversion from 'long' to 'char' changes value}}
+  return (int) BIG; // expected-warning {{implicit conversion from 'int' to 'char' changes value}}
+  return (short) BIG; // expected-warning {{implicit conversion from 'short' to 'char' changes value}}
   return (char) BIG;
 }
 
@@ -76,9 +76,9 @@ short test2(long long ll) {
   return (int) ll; // expected-warning {{implicit conversion loses integer precision}}
   return (short) ll;
   return (char) ll;
-  return (long long) BIG;  // expected-warning {{implicit conversion loses integer precision}}
-  return (long) BIG;  // expected-warning {{implicit conversion loses integer precision}}
-  return (int) BIG;  // expected-warning {{implicit conversion loses integer precision}}
+  return (long long) BIG;  // expected-warning {{implicit conversion from 'long long' to 'short' changes value}}
+  return (long) BIG;  // expected-warning {{implicit conversion from 'long' to 'short' changes value}}
+  return (int) BIG;  // expected-warning {{implicit conversion from 'int' to 'short' changes value}}
   return (short) BIG;
   return (char) BIG;
 }
@@ -89,8 +89,8 @@ int test3(long long ll) {
   return (int) ll;
   return (short) ll;
   return (char) ll;
-  return (long long) BIG;  // expected-warning {{implicit conversion loses integer precision}}
-  return (long) BIG; // expected-warning {{implicit conversion loses integer precision}}
+  return (long long) BIG;  // expected-warning {{implicit conversion from 'long long' to 'int' changes value}}
+  return (long) BIG; // expected-warning {{implicit conversion from 'long' to 'int' changes value}}
   return (int) BIG;
   return (short) BIG;
   return (char) BIG;
@@ -277,7 +277,7 @@ unsigned char test19(unsigned long u64) {
 // <rdar://problem/7631400>
 void test_7631400(void) {
   // This should show up despite the caret being inside a macro substitution
-  char s = LONG_MAX; // expected-warning {{implicit conversion loses integer precision: 'long' to 'char'}}
+  char s = LONG_MAX; // expected-warning {{implicit conversion from 'long' to 'char' changes value}}
 }
 
 // <rdar://problem/7676608>: assertion for compound operators with non-integral RHS