[Sema] Remove a -Wrange warning from -Wall

During the review of D73007 Aaron Puchert mentioned
`warn_for_range_variable_always_copy` shouldn't be part of -Wall since
some coding styles require `for(const auto &bar : bars)`. This warning
would cause false positives for these users. Based on Aaron's proposal
refactored the warnings:

* -Wrange-loop-construct warns about possibly unintended constructor
  calls. This is part of -Wall. It contains
  * warn_for_range_copy: loop variable A of type B creates a copy from
    type C
  * warn_for_range_const_reference_copy: loop variable A is initialized
    with a value of a different type resulting in a copy
* -Wrange-loop-bind-reference warns about misleading use of reference
  types. This is not part of -Wall. It contains
  * warn_for_range_variable_always_copy: loop variable A is always a copy
    because the range of type B does not return a reference

Differential Revision: https://reviews.llvm.org/D73434

clang/include/clang/Basic/DiagnosticGroups.td

@@ -384,7 +384,10 @@ def GNULabelsAsValue : DiagGroup<"gnu-label-as-value">;
 def LiteralRange : DiagGroup<"literal-range">;
 def LocalTypeTemplateArgs : DiagGroup<"local-type-template-args",
                                       [CXX98CompatLocalTypeTemplateArgs]>;
-def RangeLoopAnalysis : DiagGroup<"range-loop-analysis">;
+def RangeLoopConstruct : DiagGroup<"range-loop-construct">;
+def RangeLoopBindReference : DiagGroup<"range-loop-bind-reference">;
+def RangeLoopAnalysis : DiagGroup<"range-loop-analysis",
+                                  [RangeLoopConstruct, RangeLoopBindReference]>;
 def ForLoopAnalysis : DiagGroup<"for-loop-analysis">;
 def LoopAnalysis : DiagGroup<"loop-analysis", [ForLoopAnalysis,
                                                RangeLoopAnalysis]>;
@@ -858,14 +861,15 @@ def Most : DiagGroup<"most", [
     Comment,
     DeleteNonVirtualDtor,
     Format,
+    ForLoopAnalysis,
     Implicit,
     InfiniteRecursion,
     IntInBoolContext,
-    LoopAnalysis,
     MismatchedTags,
     MissingBraces,
     Move,
     MultiChar,
+    RangeLoopConstruct,
     Reorder,
     ReturnType,
     SelfAssignment,

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -2384,17 +2384,17 @@ def warn_for_range_const_reference_copy : Warning<
   "loop variable %0 "
   "%diff{has type $ but is initialized with type $"
   "| is initialized with a value of a different type}1,2 resulting in a copy">,
-  InGroup<RangeLoopAnalysis>, DefaultIgnore;
+  InGroup<RangeLoopConstruct>, DefaultIgnore;
 def note_use_type_or_non_reference : Note<
   "use non-reference type %0 to keep the copy or type %1 to prevent copying">;
 def warn_for_range_variable_always_copy : Warning<
   "loop variable %0 is always a copy because the range of type %1 does not "
   "return a reference">,
-  InGroup<RangeLoopAnalysis>, DefaultIgnore;
+  InGroup<RangeLoopBindReference>, DefaultIgnore;
 def note_use_non_reference_type : Note<"use non-reference type %0">;
 def warn_for_range_copy : Warning<
   "loop variable %0 of type %1 creates a copy from type %2">,
-  InGroup<RangeLoopAnalysis>, DefaultIgnore;
+  InGroup<RangeLoopConstruct>, DefaultIgnore;
 def note_use_reference_type : Note<"use reference type %0 to prevent copying">;
 def err_objc_for_range_init_stmt : Error<
   "initialization statement is not supported when iterating over Objective-C "

clang/test/Misc/warning-wall.c

@@ -15,14 +15,12 @@ CHECK-NEXT:      -Wnonnull
 CHECK-NEXT:      -Wformat-security
 CHECK-NEXT:      -Wformat-y2k
 CHECK-NEXT:      -Wformat-invalid-specifier
+CHECK-NEXT:    -Wfor-loop-analysis
 CHECK-NEXT:    -Wimplicit
 CHECK-NEXT:      -Wimplicit-function-declaration
 CHECK-NEXT:      -Wimplicit-int
 CHECK-NEXT:    -Winfinite-recursion
 CHECK-NEXT:    -Wint-in-bool-context
-CHECK-NEXT:    -Wloop-analysis
-CHECK-NEXT:      -Wfor-loop-analysis
-CHECK-NEXT:      -Wrange-loop-analysis
 CHECK-NEXT:    -Wmismatched-tags
 CHECK-NEXT:    -Wmissing-braces
 CHECK-NEXT:    -Wmove
@@ -31,6 +29,7 @@ CHECK-NEXT:      -Wredundant-move
 CHECK-NEXT:      -Wreturn-std-move
 CHECK-NEXT:      -Wself-move
 CHECK-NEXT:    -Wmultichar
+CHECK-NEXT:    -Wrange-loop-construct
 CHECK-NEXT:    -Wreorder
 CHECK-NEXT:      -Wreorder-ctor
 CHECK-NEXT:      -Wreorder-init-list

clang/test/SemaCXX/warn-range-loop-analysis.cpp

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -std=c++11 -Wall -Wno-unused -verify %s
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 -Wall -Wrange-loop-bind-reference -Wno-unused -verify %s
 // RUN: %clang_cc1 -fsyntax-only -std=c++11 -Wloop-analysis -verify %s
 // RUN: %clang_cc1 -fsyntax-only -std=c++11 -Wrange-loop-analysis -verify %s
 // RUN: %clang_cc1 -fsyntax-only -std=c++11 -Wloop-analysis -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s