Index: include/clang/AST/Expr.h
===================================================================
--- include/clang/AST/Expr.h
+++ include/clang/AST/Expr.h
@@ -116,6 +116,7 @@
     ExprBits.ValueKind = VK;
     ExprBits.ObjectKind = OK;
     ExprBits.ContainsUnexpandedParameterPack = ContainsUnexpandedParameterPack;
+    ExprBits.IsCondition = 0;
     setType(T);
   }
 
@@ -219,6 +220,17 @@
     ExprBits.ContainsUnexpandedParameterPack = PP;
   }
 
+  /// \brief Whether this expression appears in condition expression context.
+  bool isCondition() const {
+    return ExprBits.IsCondition;
+  }
+
+  /// \brief Set the bit that describes whether this expression
+  /// appears in condition context e.g.: if(expr) while(expr) ?: etc.
+  void setIsCondition(bool PP = true) {
+    ExprBits.IsCondition = PP;
+  }
+
   /// getExprLoc - Return the preferred location for the arrow when diagnosing
   /// a problem with a generic expression.
   SourceLocation getExprLoc() const LLVM_READONLY;
Index: include/clang/AST/Stmt.h
===================================================================
--- include/clang/AST/Stmt.h
+++ include/clang/AST/Stmt.h
@@ -131,8 +131,9 @@
     unsigned ValueDependent : 1;
     unsigned InstantiationDependent : 1;
     unsigned ContainsUnexpandedParameterPack : 1;
+    unsigned IsCondition : 1;
   };
-  enum { NumExprBits = 16 };
+  enum { NumExprBits = 17 };
 
   class CharacterLiteralBitfields {
     friend class CharacterLiteral;
Index: lib/Parse/ParseExpr.cpp
===================================================================
--- lib/Parse/ParseExpr.cpp
+++ lib/Parse/ParseExpr.cpp
@@ -309,6 +309,8 @@
         TernaryMiddle = nullptr;
         Diag(Tok, diag::ext_gnu_conditional_expr);
       }
+      if (!LHS.isInvalid()) 
+        LHS.get()->setIsCondition();
 
       if (!TryConsumeToken(tok::colon, ColonLoc)) {
         // Otherwise, we're missing a ':'.  Assume that this was a typo that
Index: lib/Sema/SemaChecking.cpp
===================================================================
--- lib/Sema/SemaChecking.cpp
+++ lib/Sema/SemaChecking.cpp
@@ -9020,6 +9020,10 @@
       if (S.SourceMgr.isInSystemMacro(CC))
         return;
 
+      // Suppress float-to-bool diagnostic in conditions.
+      if (TargetBT->isBooleanType() && E->isCondition())
+        return;
+
       DiagnoseFloatingImpCast(S, E, T, CC);
     }
 
@@ -9222,7 +9226,10 @@
 /// of competing diagnostics here, -Wconversion and -Wsign-compare.
 void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) {
   QualType T = OrigE->getType();
+  bool isCondition = OrigE->isCondition();
   Expr *E = OrigE->IgnoreParenImpCasts();
+  if (isCondition)
+    E->setIsCondition(isCondition);
 
   if (E->isTypeDependent() || E->isValueDependent())
     return;
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp
+++ lib/Sema/SemaExpr.cpp
@@ -14607,10 +14607,12 @@
   ExprResult Cond;
   switch (CK) {
   case ConditionKind::Boolean:
+    SubExpr->setIsCondition();
     Cond = CheckBooleanCondition(Loc, SubExpr);
     break;
 
   case ConditionKind::ConstexprIf:
+    SubExpr->setIsCondition();
     Cond = CheckBooleanCondition(Loc, SubExpr, true);
     break;
 
Index: lib/Sema/SemaStmt.cpp
===================================================================
--- lib/Sema/SemaStmt.cpp
+++ lib/Sema/SemaStmt.cpp
@@ -1264,6 +1264,7 @@
   if (CondResult.isInvalid())
     return StmtError();
   Cond = CondResult.get();
+  Cond->setIsCondition();
 
   CondResult = ActOnFinishFullExpr(Cond, DoLoc);
   if (CondResult.isInvalid())
Index: test/SemaCXX/warn-float-conversion.cpp
===================================================================
--- test/SemaCXX/warn-float-conversion.cpp
+++ test/SemaCXX/warn-float-conversion.cpp
@@ -87,3 +87,29 @@
   char e = 1.0 / 0.0;  // expected-warning{{implicit conversion of out of range value from 'double' to 'char' changes value from +Inf to 127}}
 }
 #endif  // OVERFLOW
+
+int m(int argc)
+{
+  float f = argc;
+  // Test that float-to-bool conversion warnings are not issued
+  // for conditions.
+ 
+
+  if (f)  	
+    return 1;
+  else  
+    return f
+           ? 1 
+           : 0;
+
+  if (f+1)  	//Question: also suppress for this expresson?
+    return 1;
+
+  while (f) ;
+
+  do ; while (f) ;
+
+  for (; f ; ) ;
+
+  return 0;
+}