re PR middle-end/67338 (fold-const sanitizer runtime error in roundup_loc)

	PR c/67338
	* fold-const.c (round_up_loc): Negate divisor in unsigned type to
	avoid UB.

	* gcc.dg/pr67338.c: New test.

From-SVN: r246305

gcc/ChangeLog

+2017-03-21  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/67338
+	* fold-const.c (round_up_loc): Negate divisor in unsigned type to
+	avoid UB.
+
 2017-03-20  Segher Boessenkool  <segher@kernel.crashing.org>
 
 	PR rtl-optimization/79910

gcc/fold-const.c

@@ -14250,7 +14250,7 @@ round_up_loc (location_t loc, tree value, unsigned int divisor)
 
 	  overflow_p = TREE_OVERFLOW (value);
 	  val += divisor - 1;
-	  val &= - (int) divisor;
+	  val &= (int) -divisor;
 	  if (val == 0)
 	    overflow_p = true;
 

gcc/testsuite/ChangeLog

 2017-03-21  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c/67338
+	* gcc.dg/pr67338.c: New test.
+
 	PR c++/35878
 	* g++.dg/init/pr35878_1.C: Rewrite directives to scan optimized
 	dump instead of assembler.

gcc/testsuite/gcc.dg/pr67338.c

+/* PR c/67338 */
+/* { dg-do compile { target *-*-linux* *-*-gnu* } } */
+
+struct S { __attribute__((aligned (1 << 28))) double a; };