Make the integer-range analysis recognize ^= correctly,

and (while I'm at it) teach it to grok the results of simple
assignments.

The first is PR10336.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@135034 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 26 insertions, 2 deletions

diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 8bad032911..267cda8f40 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -2586,15 +2586,24 @@ IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) {
     case BO_NE:
       return IntRange::forBoolType();
 
-    // The type of these compound assignments is the type of the LHS,
-    // so the RHS is not necessarily an integer.
+    // The type of the assignments is the type of the LHS, so the RHS
+    // is not necessarily the same type.
     case BO_MulAssign:
     case BO_DivAssign:
     case BO_RemAssign:
     case BO_AddAssign:
     case BO_SubAssign:
+    case BO_XorAssign:
+    case BO_OrAssign:
+      // TODO: bitfields?
       return IntRange::forValueOfType(C, E->getType());
 
+    // Simple assignments just pass through the RHS, which will have
+    // been coerced to the LHS type.
+    case BO_Assign:
+      // TODO: bitfields?
+      return GetExprRange(C, BO->getRHS(), MaxWidth);
+
     // Operations with opaque sources are black-listed.
     case BO_PtrMemD:
     case BO_PtrMemI:
diff --git a/test/Sema/compare.c b/test/Sema/compare.c
index 5221b172a6..cd973d4885 100644
--- a/test/Sema/compare.c
+++ b/test/Sema/compare.c
@@ -312,3 +312,18 @@ int rdar8511238() {
     return 0;
   return 20;
 }
+
+// PR10336
+int test9(int sv, unsigned uv, long slv) {
+  return sv == (uv ^= slv); // expected-warning {{comparison of integers of different signs: 'int' and 'unsigned int'}}
+}
+
+void test10(void) {
+  int si;
+  unsigned int ui;
+  long sl;
+
+  _Bool b;
+  b = (si == (ui = sl)); // expected-warning {{comparison of integers of different signs: 'int' and 'unsigned int'}}
+  b = (si == (ui = sl&15));
+}