From: jason <jason@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Fri, 20 Nov 2015 15:51:35 +0000 (+0000)
Subject: 	* c-common.c (shorten_compare): But look through macros from
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=01f11119603eae9fc41f216d61c6c296a53d4011;p=thirdparty%2Fgcc.git

	* c-common.c (shorten_compare): But look through macros from
	system headers.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@230665 138bc75d-0d04-0410-961f-82ee72b054a4
---

diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 5ca75b4dbf00..c19cafa05f88 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,8 @@
+2015-11-19  Jason Merrill  <jason@redhat.com>
+
+	* c-common.c (shorten_compare): But look through macros from
+	system headers.
+
 2015-11-18  Jason Merrill  <jason@redhat.com>
 
 	* c-common.c (shorten_compare): Don't -Wtype-limits if the
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 068a0bcd2ec0..fe0a235988fe 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -4651,8 +4651,10 @@ shorten_compare (location_t loc, tree *op0_ptr, tree *op1_ptr,
 	}
 
       if (TREE_CODE (primop0) != INTEGER_CST
-	  /* Don't warn if it's from a macro.  */
-	  && !from_macro_expansion_at (EXPR_LOCATION (primop0)))
+	  /* Don't warn if it's from a (non-system) macro.  */
+	  && !(from_macro_expansion_at
+	       (expansion_point_location_if_in_system_header
+		(EXPR_LOCATION (primop0)))))
 	{
 	  if (val == truthvalue_false_node)
 	    warning_at (loc, OPT_Wtype_limits,
diff --git a/gcc/testsuite/gcc.dg/Wtype-limits2.c b/gcc/testsuite/gcc.dg/Wtype-limits2.c
new file mode 100644
index 000000000000..92151aa68c9c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wtype-limits2.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-Wtype-limits" } */
+/* { dg-require-effective-target sync_char_short } */
+
+#include <stdatomic.h>
+
+unsigned foo (unsigned char *x)
+{
+  if (atomic_load (x) > 1000) /* { dg-warning "comparison is always false due to limited range of data type" } */
+    return 0;
+  return 1;
+}