Fix rdar://8139785 "implement warning on dead expression in comma operator"

As a bonus, fix the warning for || and && operators; it was emitted even if one of the operands had side effects, e.g:

x || test_logical_foo1();

emitted a bogus "expression result unused" for 'x'.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@107274 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 13 insertions, 3 deletions

diff --git a/test/Sema/warn-unused-value.c b/test/Sema/warn-unused-value.c
index 16b787f774..1a7e745785 100644
--- a/test/Sema/warn-unused-value.c
+++ b/test/Sema/warn-unused-value.c
@@ -18,9 +18,9 @@ void pr4806() {
   i,foo();          // expected-warning {{expression result unused}}
   foo(),i;          // expected-warning {{expression result unused}}
 
-  i,j,foo();        // expected-warning {{expression result unused}}
-  i,foo(),j;        // expected-warning {{expression result unused}}
-  foo(),i,j;        // expected-warning {{expression result unused}}
+  i,j,foo();        // expected-warning {{expression result unused}} expected-warning {{expression result unused}}
+  i,foo(),j;        // expected-warning {{expression result unused}} expected-warning {{expression result unused}}
+  foo(),i,j;        // expected-warning {{expression result unused}} expected-warning {{expression result unused}}
 
   i++;
 
@@ -63,6 +63,16 @@ int test_logical_bar() {
   (x = test_logical_foo1()) ||  // no-warning
   (x = test_logical_foo2()) ||  // no-warning
   (x = test_logical_foo3());    // no-warning
+
+  x || test_logical_foo1();     // no-warning
+
   return x;
 }
 
+struct s0 { int f0; };
+
+void f0(int a);
+void f1(struct s0 *a) {
+  // rdar://8139785
+  f0((int)(a->f0 + 1, 10)); // expected-warning {{expression result unused}}
+}