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Re: [PATCH] Introduce TYPE_OVERFLOW_SANITIZED


On Thu, Nov 13, 2014 at 09:45:50AM +0100, Richard Biener wrote:
> Hmm, I'd have expected to test !TYPE_OVERFLOW_SANITIZED (),
> that is, have the predicate inverted.  At least that's how
> I understand the name - an overflow is to be preserved for
> sanitization.
 
I guess that macro name is a little bit baffling ;).

> So - can you invert the predicates (and uses)?  In the
> sanitizer you then can guard instrumentations with
> TYPE_OVERFLOW_SANITIZED.
 
Done.

> Ok with that change.

Thanks, this is the inverted version:

2014-11-13  Marek Polacek  <polacek@redhat.com>

	* tree.h (TYPE_OVERFLOW_SANITIZED): Define.
	* fold-const.c (fold_binary_loc): Use it.
	* match.pd: Likewise.

diff --git gcc/fold-const.c gcc/fold-const.c
index 4321b1e..8c19c1f 100644
--- gcc/fold-const.c
+++ gcc/fold-const.c
@@ -10538,9 +10538,7 @@ fold_binary_loc (location_t loc,
 
       /* A - B -> A + (-B) if B is easily negatable.  */
       if (negate_expr_p (arg1)
-	  && (!INTEGRAL_TYPE_P (type)
-	      || TYPE_OVERFLOW_WRAPS (type)
-	      || (flag_sanitize & SANITIZE_SI_OVERFLOW) == 0)
+	  && !TYPE_OVERFLOW_SANITIZED (type)
 	  && ((FLOAT_TYPE_P (type)
                /* Avoid this transformation if B is a positive REAL_CST.  */
 	       && (TREE_CODE (arg1) != REAL_CST
diff --git gcc/match.pd gcc/match.pd
index 1d7b153..9a1ce93 100644
--- gcc/match.pd
+++ gcc/match.pd
@@ -285,26 +285,20 @@ along with GCC; see the file COPYING3.  If not see
   /* Apply STRIP_NOPS on @0 and the negate.  */
   (if (tree_nop_conversion_p (type, TREE_TYPE (@0))
        && tree_nop_conversion_p (type, TREE_TYPE (@1))
-       && (!INTEGRAL_TYPE_P (type)
-	   || TYPE_OVERFLOW_WRAPS (type)
-	   || (flag_sanitize & SANITIZE_SI_OVERFLOW) == 0))
+       && !TYPE_OVERFLOW_SANITIZED (type))
    (minus (convert @0) (convert @1))))
  /* A - (-B) -> A + B */
  (simplify
   (minus (convert1? @0) (convert2? (negate @1)))
   (if (tree_nop_conversion_p (type, TREE_TYPE (@0))
        && tree_nop_conversion_p (type, TREE_TYPE (@1))
-       && (!INTEGRAL_TYPE_P (type)
-	   || TYPE_OVERFLOW_WRAPS (type)
-	   || (flag_sanitize & SANITIZE_SI_OVERFLOW) == 0))
+       && !TYPE_OVERFLOW_SANITIZED (type))
    (plus (convert @0) (convert @1))))
  /* -(-A) -> A */
  (simplify
   (negate (convert? (negate @1)))
   (if (tree_nop_conversion_p (type, TREE_TYPE (@1))
-       && (!INTEGRAL_TYPE_P (type)
-	   || TYPE_OVERFLOW_WRAPS (type)
-	   || (flag_sanitize & SANITIZE_SI_OVERFLOW) == 0))
+       && !TYPE_OVERFLOW_SANITIZED (type))
    (convert @1)))
 
  /* We can't reassociate floating-point or fixed-point plus or minus
diff --git gcc/tree.h gcc/tree.h
index 0577d51..108b52d 100644
--- gcc/tree.h
+++ gcc/tree.h
@@ -789,6 +789,12 @@ extern void omp_clause_range_check_failed (const_tree, const char *, int,
 #define TYPE_OVERFLOW_TRAPS(TYPE) \
   (!TYPE_UNSIGNED (TYPE) && flag_trapv)
 
+/* True if an overflow is to be preserved for sanitization.  */
+#define TYPE_OVERFLOW_SANITIZED(TYPE)			\
+  (INTEGRAL_TYPE_P (TYPE)				\
+   && !TYPE_OVERFLOW_WRAPS (TYPE)			\
+   && (flag_sanitize & SANITIZE_SI_OVERFLOW))
+
 /* True if pointer types have undefined overflow.  */
 #define POINTER_TYPE_OVERFLOW_UNDEFINED (flag_strict_overflow)
 

	Marek


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