The rs6000 target was hitting a bootstrap failure due to
-Werror=type-limits. Since warn_tautological_cmp and other warnings
avoid warning if one of the operands comes from a macro, I thought it
would make sense to do that here as well.
Tested that this allows rs6000 bootstrap to proceed, regression tested
on x86_64-pc-linux-gnu, applying to trunk. David, do you want to revert
the #pragma GCC diagnostic change?
commit 3d382500ccb766eb1c6dea69a32348d62c86b950
Author: Jason Merrill <ja...@redhat.com>
Date: Wed Nov 18 16:30:06 2015 -0500
* c-common.c (shorten_compare): Don't -Wtype-limits if the
non-constant operand comes from a macro.
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index f50ca48..068a0bc 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -4650,7 +4650,9 @@ shorten_compare (location_t loc, tree *op0_ptr, tree *op1_ptr,
type = c_common_unsigned_type (type);
}
- if (TREE_CODE (primop0) != INTEGER_CST)
+ if (TREE_CODE (primop0) != INTEGER_CST
+ /* Don't warn if it's from a macro. */
+ && !from_macro_expansion_at (EXPR_LOCATION (primop0)))
{
if (val == truthvalue_false_node)
warning_at (loc, OPT_Wtype_limits,
diff --git a/gcc/testsuite/g++.dg/warn/Wtype-limits2.C b/gcc/testsuite/g++.dg/warn/Wtype-limits2.C
new file mode 100644
index 0000000..a46baad
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wtype-limits2.C
@@ -0,0 +1,11 @@
+// { dg-options -Wtype-limits }
+
+unsigned char array[4];
+bool b;
+#define VAL (b ? array[0] : (unsigned char)0)
+
+int main()
+{
+ if (VAL > 1000)
+ __builtin_abort();
+}
