C++ PATCH for sanitizer/80348, ICE with -fsanitize=integer-divide-by-zero

[Marek Polacek]

This ICEs in ubsan_instrument_division on the assert that checks whether both
operands of the division have the same type.  Well, here they didn't, because
in cp_build_binary_op we first converted both operands to result_type but then
fold_non_dependent_expr changed the type of op0, so we need to catch this case
before calling ubsan_instrument_division.

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

2017-04-07  Marek Polacek  <pola...@redhat.com>

        PR sanitizer/80348
        * typeck.c (cp_build_binary_op): Convert COP[01] to ORIG_TYPE.

        * g++.dg/ubsan/div-by-zero-2.C: New test.

diff --git gcc/cp/typeck.c gcc/cp/typeck.c
index 79391c0..65a3435 100644
--- gcc/cp/typeck.c
+++ gcc/cp/typeck.c
@@ -5218,10 +5218,12 @@ cp_build_binary_op (location_t location,
             original result_type.  */
          tree cop0 = op0;
          tree cop1 = op1;
-         if (orig_type != NULL && result_type != orig_type)
+         if (orig_type != NULL_TREE)
            {
-             cop0 = cp_convert (orig_type, op0, complain);
-             cop1 = cp_convert (orig_type, op1, complain);
+             if (TREE_TYPE (cop0) != orig_type)
+               cop0 = cp_convert (orig_type, op0, complain);
+             if (TREE_TYPE (cop1) != orig_type)
+               cop1 = cp_convert (orig_type, op1, complain);
            }
          instrument_expr = ubsan_instrument_division (location, cop0, cop1);
        }
diff --git gcc/testsuite/g++.dg/ubsan/div-by-zero-2.C 
gcc/testsuite/g++.dg/ubsan/div-by-zero-2.C
index e69de29..d500ae6 100644
--- gcc/testsuite/g++.dg/ubsan/div-by-zero-2.C
+++ gcc/testsuite/g++.dg/ubsan/div-by-zero-2.C
@@ -0,0 +1,10 @@
+// PR sanitizer/80348
+// { dg-do compile }
+// { dg-options "-fsanitize=integer-divide-by-zero" }
+
+void
+foo ()
+{
+  if (0)
+    unsigned ((0 != 60806) > (0 != 0)) / 0; // { dg-warning "division by zero" 
}
+}

        Marek