On Wed, Nov 12, 2014 at 10:49:38AM +0100, Richard Biener wrote:
> TYPE_OVERFLOW_WRAPS returns nonsense for !integral types and thus
> this check likely restricts the transform to non-floats for example.
> The macro documentation states "given an integral type ..." thus
> it should be sth like
>
> && (!INTEGRAL_TYPE_P (type)
> || TYPE_OVERFLOW_WRAPS (type)
> || (flag_sanitize ...
Ah, I can see now.
> and the TYPE_OVERFLOW_* macros should probably be guarded with
> tree checking against use on non-integral types (you might want
> to do that as a followup).
Sure.
> > && ((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 29b5ab2..5a485f3 100644
> > --- gcc/match.pd
> > +++ gcc/match.pd
> > @@ -291,7 +291,9 @@ along with GCC; see the file COPYING3. If not see
> > (simplify
> > (minus (convert1? @0) (convert2? (negate @1)))
> > (if (tree_nop_conversion_p (type, TREE_TYPE (@0))
> > - && tree_nop_conversion_p (type, TREE_TYPE (@1)))
> > + && tree_nop_conversion_p (type, TREE_TYPE (@1))
> > + && (TYPE_OVERFLOW_WRAPS (type)
> > + || (flag_sanitize & SANITIZE_SI_OVERFLOW) == 0))
>
> This has the same issue with unnecessarily restricting FLOAT types, so
> can you fix that here and in the two other patterns already guarded
> with flag_sanitize?
Done. Note that one pattern had SANITIZE_SI_OVERFLOW check, but not
the TYPE_OVERFLOW_WRAPS check. Which leads me to thinking that we
might want a new predicate for
(!INTEGRAL_TYPE_P (type)
|| TYPE_OVERFLOW_WRAPS (type)
|| (flag_sanitize ...))
Do you agree? If so, I'll do that as another followup.
> Ok with that changes.
Thanks, I'll install the following then.
2014-11-12 Marek Polacek <pola...@redhat.com>
* fold-const.c (fold_binary_loc): Don't fold if the result
is undefined.
* match.pd (A + (-B) -> A - B, A - (-B) -> A + B,
-(-A) -> A): Likewise.
* c-c++-common/ubsan/overflow-sub-4.c: New test.
* c-c++-common/ubsan/overflow-sub-2.c: Adjust dg-output.
* c-c++-common/ubsan/overflow-int128.c: Likewise.
diff --git gcc/fold-const.c gcc/fold-const.c
index 756f469..85fada3 100644
--- gcc/fold-const.c
+++ gcc/fold-const.c
@@ -10544,6 +10544,9 @@ 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)
&& ((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 39abe25..4e5e6c5 100644
--- gcc/match.pd
+++ gcc/match.pd
@@ -285,19 +285,25 @@ 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))
- && (flag_sanitize & SANITIZE_SI_OVERFLOW) == 0)
+ && (!INTEGRAL_TYPE_P (type)
+ || TYPE_OVERFLOW_WRAPS (type)
+ || (flag_sanitize & SANITIZE_SI_OVERFLOW) == 0))
(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)))
+ && tree_nop_conversion_p (type, TREE_TYPE (@1))
+ && (!INTEGRAL_TYPE_P (type)
+ || TYPE_OVERFLOW_WRAPS (type)
+ || (flag_sanitize & SANITIZE_SI_OVERFLOW) == 0))
(plus (convert @0) (convert @1))))
/* -(-A) -> A */
(simplify
(negate (convert? (negate @1)))
(if (tree_nop_conversion_p (type, TREE_TYPE (@1))
- && (TYPE_OVERFLOW_WRAPS (type)
+ && (!INTEGRAL_TYPE_P (type)
+ || TYPE_OVERFLOW_WRAPS (type)
|| (flag_sanitize & SANITIZE_SI_OVERFLOW) == 0))
(convert @1)))
diff --git gcc/testsuite/c-c++-common/ubsan/overflow-int128.c
gcc/testsuite/c-c++-common/ubsan/overflow-int128.c
index 125d6bf..4384d7c 100644
--- gcc/testsuite/c-c++-common/ubsan/overflow-int128.c
+++ gcc/testsuite/c-c++-common/ubsan/overflow-int128.c
@@ -41,7 +41,7 @@ main (void)
/* { dg-output "\[^\n\r]*signed integer overflow:
0x7fffffffffffffffffffffffffffff9b \\+ 1024 cannot be represented in type
'__int128'(\n|\r\n|\r)" } */
/* { dg-output "\[^\n\r]*signed integer overflow: -1 \\+
0x80000000000000000000000000000000 cannot be represented in type
'__int128'(\n|\r\n|\r)" } */
/* { dg-output "\[^\n\r]*signed integer overflow:
0x80000000000000000000000000000000 \\+ -1 cannot be represented in type
'__int128'(\n|\r\n|\r)" } */
-/* { dg-output "\[^\n\r]*signed integer overflow:
0x80000000000000000000000000000000 \\+ -1 cannot be represented in type
'__int128'(\n|\r\n|\r)" } */
+/* { dg-output "\[^\n\r]*signed integer overflow:
0x80000000000000000000000000000000 - 1 cannot be represented in type
'__int128'(\n|\r\n|\r)" } */
/* { dg-output "\[^\n\r]*signed integer overflow:
0x80000000000000000000000000000064 \\+ -1024 cannot be represented in type
'__int128'(\n|\r\n|\r)" } */
/* { dg-output "\[^\n\r]*signed integer overflow:
0x7fffffffffffffffffffffffffffffff \\* 2 cannot be represented in type
'__int128'(\n|\r\n|\r)" } */
/* { dg-output "\[^\n\r]*negation of 0x80000000000000000000000000000000 cannot
be represented in type '__int128'; cast to an unsigned type to negate this
value to itself\[^\n\r]*(\n|\r\n|\r)" } */
diff --git gcc/testsuite/c-c++-common/ubsan/overflow-sub-2.c
gcc/testsuite/c-c++-common/ubsan/overflow-sub-2.c
index daf6a54..88c4762 100644
--- gcc/testsuite/c-c++-common/ubsan/overflow-sub-2.c
+++ gcc/testsuite/c-c++-common/ubsan/overflow-sub-2.c
@@ -43,12 +43,12 @@ main (void)
}
/* { dg-output "signed integer overflow: -2147483648 - 1 cannot be represented
in type 'int'\[^\n\r]*(\n|\r\n|\r)" } */
-/* { dg-output "\[^\n\r]*signed integer overflow: -2147483648 \\+ -1 cannot be
represented in type 'int'\[^\n\r]*(\n|\r\n|\r)" } */
-/* { dg-output "\[^\n\r]*signed integer overflow: -2147483548 \\+ -1024 cannot
be represented in type 'int'\[^\n\r]*(\n|\r\n|\r)" } */
-/* { dg-output "\[^\n\r]*signed integer overflow: -2147483648 \\+ -1 cannot be
represented in type 'int'\[^\n\r]*(\n|\r\n|\r)" } */
-/* { dg-output "\[^\n\r]*signed integer overflow: -2147482648 \\+ -1048576
cannot be represented in type 'int'\[^\n\r]*(\n|\r\n|\r)" } */
+/* { dg-output "\[^\n\r]*signed integer overflow: -2147483648 - 1 cannot be
represented in type 'int'\[^\n\r]*(\n|\r\n|\r)" } */
+/* { dg-output "\[^\n\r]*signed integer overflow: -2147483548 - 1024 cannot be
represented in type 'int'\[^\n\r]*(\n|\r\n|\r)" } */
+/* { dg-output "\[^\n\r]*signed integer overflow: -2147483648 - 1 cannot be
represented in type 'int'\[^\n\r]*(\n|\r\n|\r)" } */
+/* { dg-output "\[^\n\r]*signed integer overflow: -2147482648 - 1048576 cannot
be represented in type 'int'\[^\n\r]*(\n|\r\n|\r)" } */
/* { dg-output "\[^\n\r]*signed integer overflow: -\[^\n\r]* - 1 cannot be
represented in type 'long int'\[^\n\r]*(\n|\r\n|\r)" } */
-/* { dg-output "\[^\n\r]*signed integer overflow: -\[^\n\r]* \\+ -1 cannot be
represented in type 'long int'\[^\n\r]*(\n|\r\n|\r)" } */
-/* { dg-output "\[^\n\r]*signed integer overflow: -\[^\n\r]* \\+ -1024 cannot
be represented in type 'long int'\[^\n\r]*(\n|\r\n|\r)" } */
-/* { dg-output "\[^\n\r]*signed integer overflow: -\[^\n\r]* \\+ -1 cannot be
represented in type 'long int'\[^\n\r]*(\n|\r\n|\r)" } */
-/* { dg-output "\[^\n\r]*signed integer overflow: -\[^\n\r]* \\+ -1048576
cannot be represented in type 'long int'\[^\n\r]*" } */
+/* { dg-output "\[^\n\r]*signed integer overflow: -\[^\n\r]* - 1 cannot be
represented in type 'long int'\[^\n\r]*(\n|\r\n|\r)" } */
+/* { dg-output "\[^\n\r]*signed integer overflow: -\[^\n\r]* - 1024 cannot be
represented in type 'long int'\[^\n\r]*(\n|\r\n|\r)" } */
+/* { dg-output "\[^\n\r]*signed integer overflow: -\[^\n\r]* - 1 cannot be
represented in type 'long int'\[^\n\r]*(\n|\r\n|\r)" } */
+/* { dg-output "\[^\n\r]*signed integer overflow: -\[^\n\r]* - 1048576 cannot
be represented in type 'long int'\[^\n\r]*" } */
diff --git gcc/testsuite/c-c++-common/ubsan/overflow-sub-4.c
gcc/testsuite/c-c++-common/ubsan/overflow-sub-4.c
index e69de29..519b7ba 100644
--- gcc/testsuite/c-c++-common/ubsan/overflow-sub-4.c
+++ gcc/testsuite/c-c++-common/ubsan/overflow-sub-4.c
@@ -0,0 +1,19 @@
+/* { dg-do run } */
+/* { dg-options "-fsanitize=signed-integer-overflow" } */
+
+#define INT_MIN (-__INT_MAX__ - 1)
+
+int
+main ()
+{
+ int x = INT_MIN;
+ int y = 0;
+ int z;
+ asm ("" : "+g" (y));
+ asm ("" : "+g" (x));
+ z = y - (-x);
+ asm ("" : "+g" (z));
+}
+
+/* { dg-output "negation of -2147483648 cannot be represented in type
'int'\[^\n\r]*; cast to an unsigned type to negate this value to
itself\[^\n\r]*(\n|\r\n|\r)" } */
+/* { dg-output "\[^\n\r]*signed integer overflow: 0 - -2147483648 cannot be
represented in type 'int'\[^\n\r]*(\n|\r\n|\r)" } */
Marek
