commit 6a6af52ba604a1b837249b211e6d16cbb5ceca45
author Richard Trieu <rtrieu@google.com> Wed Jan 04 00:46:30 2017 +0000
committer Richard Trieu <rtrieu@google.com> Wed Jan 04 00:46:30 2017 +0000
tree 5b0e2e435a061860eca2f0da3c1914c5bf5a081b
parent 287d9496670c3b017a6c64b9cd701028d32a0274

Extend -Wtautological-overlap-compare to more cases.

Previously, -Wtautological-overlap-compare did not warn on cases where the
boolean expression was in an assignment or return statement.  This patch
should cause all boolean statements to be passed to the tautological compare
checks in the CFG analysis.

This is one of the issues from PR13101

llvm-svn: 290920

clang/test/Sema/warn-overlap.c

diff --git a/clang/test/Sema/warn-overlap.c b/clang/test/Sema/warn-overlap.c
index 1e8a614..6299c51 100644
--- a/clang/test/Sema/warn-overlap.c
+++ b/clang/test/Sema/warn-overlap.c
@@ -96,3 +96,48 @@
   int buffer[4];
   x = (-7 > 0) ? (buffer[-7]) : 0;
 }
+
+void bool_contexts(int x) {
+  if (x > 4 || x < 10) {}
+  // expected-warning@-1{{overlapping comparisons always evaluate to true}}
+  for (;x > 4 || x < 10;) {}
+  // expected-warning@-1{{overlapping comparisons always evaluate to true}}
+  while (x > 4 || x < 10) {}
+  // expected-warning@-1{{overlapping comparisons always evaluate to true}}
+  do {} while (x > 4 || x < 10);
+  // expected-warning@-1{{overlapping comparisons always evaluate to true}}
+  x = (x > 4 || x < 10) ? 1 : 2;
+  // expected-warning@-1{{overlapping comparisons always evaluate to true}}
+  if ((void)5, x > 4 || x < 10) {}
+  // expected-warning@-1{{overlapping comparisons always evaluate to true}}
+}
+
+void assignment(int x) {
+  int a = x > 4 || x < 10;
+  // expected-warning@-1{{overlapping comparisons always evaluate to true}}
+  int b = x < 2 && x > 5;
+  // expected-warning@-1{{overlapping comparisons always evaluate to false}}
+
+  int c = x != 1 || x != 3;
+  // expected-warning@-1{{overlapping comparisons always evaluate to true}}
+  int d = x == 1 && x == 2;
+  // expected-warning@-1{{overlapping comparisons always evaluate to false}}
+
+  int e = x < 1 || x != 0;
+  // expected-warning@-1{{overlapping comparisons always evaluate to true}}
+}
+
+int returns(int x) {
+  return x > 4 || x < 10;
+  // expected-warning@-1{{overlapping comparisons always evaluate to true}}
+  return x < 2 && x > 5;
+  // expected-warning@-1{{overlapping comparisons always evaluate to false}}
+
+  return x != 1 || x != 3;
+  // expected-warning@-1{{overlapping comparisons always evaluate to true}}
+  return x == 1 && x == 2;
+  // expected-warning@-1{{overlapping comparisons always evaluate to false}}
+
+  return x < 1 || x != 0;
+  // expected-warning@-1{{overlapping comparisons always evaluate to true}}
+}