[PATCH] Fix fold_binary_loc BIT_IOR_EXPR folding (PR sanitizer/80349)

[Marek Polacek]

Here we are crashing because fold_binary_loc produced a BIT_IOR_EXPR with
incompatible operands.  Fixed by adding the missing conversion, similarly
to <https://gcc.gnu.org/ml/gcc-patches/2017-04/msg00551.html>.

Bootstrapped/regtested on x86_64-linux, ok for trunk?  And 7.1?

2017-04-25  Marek Polacek  <pola...@redhat.com>

        PR sanitizer/80349
        * fold-const.c (fold_binary_loc) <case BIT_IOR_EXPR>: Convert arg0's
        first argument to type.

        * g++.dg/ubsan/pr80349-2.C: New test.

diff --git gcc/fold-const.c gcc/fold-const.c
index f0b8e7a..ce4b2df 100644
--- gcc/fold-const.c
+++ gcc/fold-const.c
@@ -9898,8 +9898,10 @@ fold_binary_loc (location_t loc,
 
          /* If (C1|C2) == ~0 then (X&C1)|C2 becomes X|C2.  */
          if (msk.and_not (c1 | c2) == 0)
-           return fold_build2_loc (loc, BIT_IOR_EXPR, type,
-                                   TREE_OPERAND (arg0, 0), arg1);
+           {
+             tem = fold_convert_loc (loc, type, TREE_OPERAND (arg0, 0));
+             return fold_build2_loc (loc, BIT_IOR_EXPR, type, tem, arg1);
+           }
 
          /* Minimize the number of bits set in C1, i.e. C1 := C1 & ~C2,
             unless (C1 & ~C2) | (C2 & C3) for some C3 is a mask of some
diff --git gcc/testsuite/g++.dg/ubsan/pr80349-2.C 
gcc/testsuite/g++.dg/ubsan/pr80349-2.C
index e69de29..ca5ea4a 100644
--- gcc/testsuite/g++.dg/ubsan/pr80349-2.C
+++ gcc/testsuite/g++.dg/ubsan/pr80349-2.C
@@ -0,0 +1,11 @@
+// PR sanitizer/80349
+// { dg-do compile }
+// { dg-options "-fsanitize=undefined" }
+
+unsigned long int ll;
+
+int
+foo ()
+{
+  return (2036854775807 >> ll & char(207648476159223) | 502810590243120797UL) 
<< 0;
+}

        Marek