[PATCH] D65192: [Sema] Disable some enabled-by-default -Wparentheses diagnostics

[Fangrui Song via Phabricator via cfe-commits]

MaskRay created this revision.
MaskRay added reviewers: akyrtzi, jyknight, rtrieu, rsmith.
Herald added subscribers: cfe-commits, dexonsmith.
Herald added a project: clang.

The -Wparentheses warnings are enabled by default in clang but they are under
-Wall in gcc (gcc/c-family/c.opt). Many of the operator precedence warnings are
oftentimes criticized as noise (clang: default; gcc: -Wall). If a warning is
very controversial, it is probably not a good idea to enable it by default.
This patch disables the rather annoying ones:

-Wbitwise-op-parentheses, e.g. i & i | i
-Wlogical-op-parentheses, e.g. i && i || i
-Wshift-op-parentheses (and -Woverloaded-shift-op-parentheses), e.g. i+i << i

After this change:

  * = enabled by default
  
  -Wall
    -Wmost
      -Wparentheses
        -Wlogical-op-parentheses
        -Wlogical-not-parentheses*
        -Wbitwise-op-parentheses
        -Wshift-op-parentheses
        -Woverloaded-shift-op-parentheses
        -Wparentheses-equality*
        -Wdangling-else*


Repository:
  rC Clang

https://reviews.llvm.org/D65192

Files:
  include/clang/Basic/DiagnosticSemaKinds.td
  test/Misc/warning-flags-enabled.c
  test/Parser/cxx2a-spaceship.cpp
  test/SemaCXX/parentheses.cpp


Index: test/SemaCXX/parentheses.cpp
===================================================================
--- test/SemaCXX/parentheses.cpp
+++ test/SemaCXX/parentheses.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -verify %s
+// RUN: %clang_cc1 -verify -Wlogical-op-parentheses %s
 
 // PR16930, PR16727:
 template<class Foo>
Index: test/Parser/cxx2a-spaceship.cpp
===================================================================
--- test/Parser/cxx2a-spaceship.cpp
+++ test/Parser/cxx2a-spaceship.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -std=c++2a -verify %s
+// RUN: %clang_cc1 -std=c++2a -verify -Wparentheses %s
 
 template<int> struct X {};
 
Index: test/Misc/warning-flags-enabled.c
===================================================================
--- test/Misc/warning-flags-enabled.c
+++ test/Misc/warning-flags-enabled.c
@@ -36,7 +36,7 @@
 
 // Test if -Wshift-op-parentheses is a subgroup of -Wparentheses
 // RUN: diagtool show-enabled --no-levels -Wno-parentheses -Wshift-op-parentheses %s | FileCheck --check-prefix CHECK-SHIFT-OP-PARENTHESES %s
-// RUN: diagtool show-enabled --no-levels %s | FileCheck --check-prefix CHECK-SHIFT-OP-PARENTHESES %s
+// RUN: diagtool show-enabled --no-levels %s | FileCheck --check-prefix CHECK-NO-SHIFT-OP-PARENTHESES %s
 // RUN: diagtool show-enabled --no-levels -Wno-parentheses %s | FileCheck --check-prefix CHECK-NO-SHIFT-OP-PARENTHESES %s
 //
 // CHECK-SHIFT-OP-PARENTHESES: -Wshift-op-parentheses
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -5639,21 +5639,21 @@
   "remove constant to silence this warning">;
 
 def warn_bitwise_op_in_bitwise_op : Warning<
-  "'%0' within '%1'">, InGroup<BitwiseOpParentheses>;
+  "'%0' within '%1'">, InGroup<BitwiseOpParentheses>, DefaultIgnore;
 
 def warn_logical_and_in_logical_or : Warning<
-  "'&&' within '||'">, InGroup<LogicalOpParentheses>;
+  "'&&' within '||'">, InGroup<LogicalOpParentheses>, DefaultIgnore;
 
 def warn_overloaded_shift_in_comparison :Warning<
   "overloaded operator %select{>>|<<}0 has higher precedence than "
   "comparison operator">,
-  InGroup<OverloadedShiftOpParentheses>;
+  InGroup<OverloadedShiftOpParentheses>, DefaultIgnore;
 def note_evaluate_comparison_first :Note<
   "place parentheses around comparison expression to evaluate it first">;
 
 def warn_addition_in_bitshift : Warning<
   "operator '%0' has lower precedence than '%1'; "
-  "'%1' will be evaluated first">, InGroup<ShiftOpParentheses>;
+  "'%1' will be evaluated first">, InGroup<ShiftOpParentheses>, DefaultIgnore;
 
 def warn_self_assignment_builtin : Warning<
   "explicitly assigning value of variable of type %0 to itself">,


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