Let's beef up warn_for_sign_compare checks; we'd folded the operands
and they could've become garbage.
Bootstrapped/regtested on x86_64-linux, ok for trunk?
2018-03-02 Marek Polacek <pola...@redhat.com>
PR c++/84171
* c-warn.c (warn_for_sign_compare): Bail out if any of the operands
is erroneous.
* g++.dg/warn/Wsign-compare-8.C: New test.
diff --git gcc/c-family/c-warn.c gcc/c-family/c-warn.c
index f3fb62c7e62..7c385959c4f 100644
--- gcc/c-family/c-warn.c
+++ gcc/c-family/c-warn.c
@@ -1931,6 +1931,9 @@ warn_for_sign_compare (location_t location,
tree op0, tree op1,
tree result_type, enum tree_code resultcode)
{
+ if (error_operand_p (orig_op0) || error_operand_p (orig_op1))
+ return;
+
int op0_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op0));
int op1_signed = !TYPE_UNSIGNED (TREE_TYPE (orig_op1));
int unsignedp0, unsignedp1;
diff --git gcc/testsuite/g++.dg/warn/Wsign-compare-8.C
gcc/testsuite/g++.dg/warn/Wsign-compare-8.C
index e69de29bb2d..237ba84d526 100644
--- gcc/testsuite/g++.dg/warn/Wsign-compare-8.C
+++ gcc/testsuite/g++.dg/warn/Wsign-compare-8.C
@@ -0,0 +1,8 @@
+// PR c++/84171
+// { dg-options "-Wsign-compare" }
+
+bool foo (char c)
+{
+ const int i = 0 = 0; // { dg-error "lvalue" }
+ return c = i;
+} // { dg-warning "control reaches" }
Marek
