From: Jakub Jelinek Date: Wed, 6 Dec 2017 19:22:06 +0000 (+0100) Subject: re PR sanitizer/81281 (UBSAN: false positive, dropped promotion to long type.) X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=d7f44d4d00640240af8731911eed207eca5ac4d0;p=gcc.git re PR sanitizer/81281 (UBSAN: false positive, dropped promotion to long type.) PR sanitizer/81281 * match.pd ((T)(P + A) - (T)P -> (T) A): Split into separate simplify for plus with :c added, and pointer_plus without that. ((T)P - (T)(P + A) -> -(T) A): Likewise. If type is integral with undefined overflow and the conversion is not widening, perform negation in utype and only convert to type afterwards. ((T)(P + A) - (T)(P + B) -> (T)A - (T)B): Split into separate simplify for plus with :c added, and pointer_plus without that. If type is integral with undefined overflow and the conversion is not widening, perform minus in utype and only convert to type afterwards. Move the last pointer_diff_expr simplify into the two outermost ifs. * gcc.c-torture/execute/pr81281.c: New test. * gcc.dg/pr81281-1.c: New test. * gcc.dg/pr81281-2.c: New test. * g++.dg/ubsan/pr81281.C: New test. * g++.dg/ubsan/pr81281-aux.cc: New test. From-SVN: r255449 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index de037da6b02..9cfc382239b 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,18 @@ +2017-12-06 Jakub Jelinek + + PR sanitizer/81281 + * match.pd ((T)(P + A) - (T)P -> (T) A): Split into separate + simplify for plus with :c added, and pointer_plus without that. + ((T)P - (T)(P + A) -> -(T) A): Likewise. If type is integral + with undefined overflow and the conversion is not widening, + perform negation in utype and only convert to type afterwards. + ((T)(P + A) - (T)(P + B) -> (T)A - (T)B): Split into separate + simplify for plus with :c added, and pointer_plus without that. + If type is integral with undefined overflow and the conversion is + not widening, perform minus in utype and only convert to type + afterwards. Move the last pointer_diff_expr simplify into the + two outermost ifs. + 2017-12-06 Martin Sebor PR tree-optimization/82646 diff --git a/gcc/match.pd b/gcc/match.pd index 53f8b86b7d5..0a4ff6bb8df 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -1783,28 +1783,32 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (bit_not @0)) /* (T)(P + A) - (T)P -> (T) A */ - (for add (plus pointer_plus) - (simplify - (minus (convert (add @@0 @1)) - (convert @0)) - (if (element_precision (type) <= element_precision (TREE_TYPE (@1)) - /* For integer types, if A has a smaller type - than T the result depends on the possible - overflow in P + A. - E.g. T=size_t, A=(unsigned)429497295, P>0. - However, if an overflow in P + A would cause - undefined behavior, we can assume that there - is no overflow. */ - || (INTEGRAL_TYPE_P (TREE_TYPE (@0)) - && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@0))) - /* For pointer types, if the conversion of A to the - final type requires a sign- or zero-extension, - then we have to punt - it is not defined which - one is correct. */ - || (POINTER_TYPE_P (TREE_TYPE (@0)) - && TREE_CODE (@1) == INTEGER_CST - && tree_int_cst_sign_bit (@1) == 0)) - (convert @1)))) + (simplify + (minus (convert (plus:c @0 @1)) + (convert @0)) + (if (element_precision (type) <= element_precision (TREE_TYPE (@1)) + /* For integer types, if A has a smaller type + than T the result depends on the possible + overflow in P + A. + E.g. T=size_t, A=(unsigned)429497295, P>0. + However, if an overflow in P + A would cause + undefined behavior, we can assume that there + is no overflow. */ + || (INTEGRAL_TYPE_P (TREE_TYPE (@0)) + && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@0)))) + (convert @1))) + (simplify + (minus (convert (pointer_plus @@0 @1)) + (convert @0)) + (if (element_precision (type) <= element_precision (TREE_TYPE (@1)) + /* For pointer types, if the conversion of A to the + final type requires a sign- or zero-extension, + then we have to punt - it is not defined which + one is correct. */ + || (POINTER_TYPE_P (TREE_TYPE (@0)) + && TREE_CODE (@1) == INTEGER_CST + && tree_int_cst_sign_bit (@1) == 0)) + (convert @1))) (simplify (pointer_diff (pointer_plus @@0 @1) @0) /* The second argument of pointer_plus must be interpreted as signed, and @@ -1813,10 +1817,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (convert (convert:stype @1)))) /* (T)P - (T)(P + A) -> -(T) A */ - (for add (plus pointer_plus) - (simplify - (minus (convert @0) - (convert (add @@0 @1))) + (simplify + (minus (convert @0) + (convert (plus:c @0 @1))) + (if (INTEGRAL_TYPE_P (type) + && TYPE_OVERFLOW_UNDEFINED (type) + && element_precision (type) <= element_precision (TREE_TYPE (@1))) + (with { tree utype = unsigned_type_for (type); } + (convert (negate (convert:utype @1)))) (if (element_precision (type) <= element_precision (TREE_TYPE (@1)) /* For integer types, if A has a smaller type than T the result depends on the possible @@ -1826,7 +1834,17 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) undefined behavior, we can assume that there is no overflow. */ || (INTEGRAL_TYPE_P (TREE_TYPE (@0)) - && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@0))) + && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@0)))) + (negate (convert @1))))) + (simplify + (minus (convert @0) + (convert (pointer_plus @@0 @1))) + (if (INTEGRAL_TYPE_P (type) + && TYPE_OVERFLOW_UNDEFINED (type) + && element_precision (type) <= element_precision (TREE_TYPE (@1))) + (with { tree utype = unsigned_type_for (type); } + (convert (negate (convert:utype @1)))) + (if (element_precision (type) <= element_precision (TREE_TYPE (@1)) /* For pointer types, if the conversion of A to the final type requires a sign- or zero-extension, then we have to punt - it is not defined which @@ -1843,10 +1861,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (negate (convert (convert:stype @1))))) /* (T)(P + A) - (T)(P + B) -> (T)A - (T)B */ - (for add (plus pointer_plus) - (simplify - (minus (convert (add @@0 @1)) - (convert (add @0 @2))) + (simplify + (minus (convert (plus:c @0 @1)) + (convert (plus:c @0 @2))) + (if (INTEGRAL_TYPE_P (type) + && TYPE_OVERFLOW_UNDEFINED (type) + && element_precision (type) <= element_precision (TREE_TYPE (@1))) + (with { tree utype = unsigned_type_for (type); } + (convert (minus (convert:utype @1) (convert:utype @2)))) (if (element_precision (type) <= element_precision (TREE_TYPE (@1)) /* For integer types, if A has a smaller type than T the result depends on the possible @@ -1856,7 +1878,17 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) undefined behavior, we can assume that there is no overflow. */ || (INTEGRAL_TYPE_P (TREE_TYPE (@0)) - && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@0))) + && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@0)))) + (minus (convert @1) (convert @2))))) + (simplify + (minus (convert (pointer_plus @@0 @1)) + (convert (pointer_plus @0 @2))) + (if (INTEGRAL_TYPE_P (type) + && TYPE_OVERFLOW_UNDEFINED (type) + && element_precision (type) <= element_precision (TREE_TYPE (@1))) + (with { tree utype = unsigned_type_for (type); } + (convert (minus (convert:utype @1) (convert:utype @2)))) + (if (element_precision (type) <= element_precision (TREE_TYPE (@1)) /* For pointer types, if the conversion of A to the final type requires a sign- or zero-extension, then we have to punt - it is not defined which @@ -1866,13 +1898,13 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) && tree_int_cst_sign_bit (@1) == 0 && TREE_CODE (@2) == INTEGER_CST && tree_int_cst_sign_bit (@2) == 0)) - (minus (convert @1) (convert @2))))))) + (minus (convert @1) (convert @2))))) (simplify (pointer_diff (pointer_plus @@0 @1) (pointer_plus @0 @2)) /* The second argument of pointer_plus must be interpreted as signed, and thus sign-extended if necessary. */ (with { tree stype = signed_type_for (TREE_TYPE (@1)); } - (minus (convert (convert:stype @1)) (convert (convert:stype @2))))) + (minus (convert (convert:stype @1)) (convert (convert:stype @2))))))) /* Simplifications of MIN_EXPR, MAX_EXPR, fmin() and fmax(). */ diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index a42348fbb77..782e04d3639 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,12 @@ +2017-12-06 Jakub Jelinek + + PR sanitizer/81281 + * gcc.c-torture/execute/pr81281.c: New test. + * gcc.dg/pr81281-1.c: New test. + * gcc.dg/pr81281-2.c: New test. + * g++.dg/ubsan/pr81281.C: New test. + * g++.dg/ubsan/pr81281-aux.cc: New test. + 2017-12-06 Martin Sebor PR tree-optimization/82646 diff --git a/gcc/testsuite/g++.dg/ubsan/pr81281-aux.cc b/gcc/testsuite/g++.dg/ubsan/pr81281-aux.cc new file mode 100644 index 00000000000..4a34a61372f --- /dev/null +++ b/gcc/testsuite/g++.dg/ubsan/pr81281-aux.cc @@ -0,0 +1,3 @@ +extern const int ci = 1716607962; +int i = -943738830; +long long ll = -43165919987465092LL; diff --git a/gcc/testsuite/g++.dg/ubsan/pr81281.C b/gcc/testsuite/g++.dg/ubsan/pr81281.C new file mode 100644 index 00000000000..a812924fa18 --- /dev/null +++ b/gcc/testsuite/g++.dg/ubsan/pr81281.C @@ -0,0 +1,26 @@ +// PR sanitizer/81281 +// { dg-do run } +// { dg-options "-fsanitize=undefined -fno-sanitize-recover=undefined" } +// { dg-additional-sources "pr81281-aux.cc" } + +extern const int ci; +extern int i; +extern long long ll; + +int +foo () +{ + int a = (int) (-2024172551 - i - (ci - ll)) + - ((int) (-2024172551 - i - (ci - ll)) + - (int) (-2024172551 - (long long)ci)); + return a; +} + +int +main () +{ + if (__SIZEOF_INT__ * __CHAR_BIT__ == 32 + && __SIZEOF_LONG_LONG__ * __CHAR_BIT__ == 64) + foo (); + return 0; +} diff --git a/gcc/testsuite/gcc.c-torture/execute/pr81281.c b/gcc/testsuite/gcc.c-torture/execute/pr81281.c new file mode 100644 index 00000000000..5d8908f0352 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/pr81281.c @@ -0,0 +1,33 @@ +/* PR sanitizer/81281 */ + +void +foo (unsigned p, unsigned a, unsigned b) +{ + unsigned q = p + 7; + if (a - (1U + __INT_MAX__) >= 2) + __builtin_unreachable (); + int d = p + b; + int c = p + a; + if (c - d != __INT_MAX__) + __builtin_abort (); +} + +void +bar (unsigned p, unsigned a) +{ + unsigned q = p + 7; + if (a - (1U + __INT_MAX__) >= 2) + __builtin_unreachable (); + int c = p; + int d = p + a; + if (c - d != -__INT_MAX__ - 1) + __builtin_abort (); +} + +int +main () +{ + foo (-1U, 1U + __INT_MAX__, 1U); + bar (-1U, 1U + __INT_MAX__); + return 0; +} diff --git a/gcc/testsuite/gcc.dg/pr81281-1.c b/gcc/testsuite/gcc.dg/pr81281-1.c new file mode 100644 index 00000000000..5fec25d4ccb --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr81281-1.c @@ -0,0 +1,150 @@ +/* PR sanitizer/81281 */ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-optimized" } */ +/* { dg-final { scan-tree-dump-not "p_\[0-9]*\\(D\\)" "optimized" } } */ + +long long +f1 (int p, int a, int b) +{ + int c = p + 1; + int d = a + 2; + int e = b + 3; + long long f = p + a; + long long g = p + b; + return f - g; +} + +long long +f2 (int p, int a, int b) +{ + int c = a + 1; + int d = p + 2; + int e = b + 3; + long long f = p + a; + long long g = p + b; + return f - g; +} + +long long +f3 (int p, int a, int b) +{ + int c = b + 1; + int d = p + 2; + int e = a + 3; + long long f = p + a; + long long g = p + b; + return f - g; +} + +signed char +f4 (int p, int a, int b) +{ + int c = p + 1; + int d = a + 2; + int e = b + 3; + signed char f = p + a; + signed char g = p + b; + return f - g; +} + +signed char +f5 (int p, int a, int b) +{ + int c = a + 1; + int d = p + 2; + int e = b + 3; + signed char f = p + a; + signed char g = p + b; + return f - g; +} + +signed char +f6 (int p, int a, int b) +{ + int c = b + 1; + int d = p + 2; + int e = a + 3; + signed char f = p + a; + signed char g = p + b; + return f - g; +} + +long long +f7 (int p, int a) +{ + int c = p + 1; + int d = a + 2; + long long f = p + a; + long long g = p; + return f - g; +} + +long long +f8 (int p, int a) +{ + int c = a + 1; + int d = p + 2; + long long f = p + a; + long long g = p; + return f - g; +} + +signed char +f9 (int p, int a) +{ + int c = p + 1; + int d = a + 2; + signed char f = p + a; + signed char g = p; + return f - g; +} + +signed char +f10 (int p, int a) +{ + int c = a + 1; + int d = p + 2; + signed char f = p + a; + signed char g = p; + return f - g; +} + +long long +f11 (int p, int a) +{ + int c = p + 1; + int d = a + 2; + long long f = p; + long long g = p + a; + return f - g; +} + +long long +f12 (int p, int a) +{ + int c = a + 1; + int d = p + 2; + long long f = p; + long long g = p + a; + return f - g; +} + +signed char +f13 (int p, int a) +{ + int c = p + 1; + int d = a + 2; + signed char f = p; + signed char g = p + a; + return f - g; +} + +signed char +f14 (int p, int a) +{ + int c = a + 1; + int d = p + 2; + signed char f = p; + signed char g = p + a; + return f - g; +} diff --git a/gcc/testsuite/gcc.dg/pr81281-2.c b/gcc/testsuite/gcc.dg/pr81281-2.c new file mode 100644 index 00000000000..ba2c648167d --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr81281-2.c @@ -0,0 +1,80 @@ +/* PR sanitizer/81281 */ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-optimized" } */ +/* { dg-final { scan-tree-dump-not "p_\[0-9]*\\(D\\)" "optimized" } } */ + +typedef __SIZE_TYPE__ size_t; +typedef __INTPTR_TYPE__ T; + +T +f1 (char *p, size_t a, size_t b) +{ + char *c = p + 1; + size_t d = a + 2; + size_t e = b + 3; + T f = (T) (p + a); + T g = (T) (p + b); + return f - g; +} + +T +f2 (char *p, size_t a, size_t b) +{ + size_t c = a + 1; + char *d = p + 2; + size_t e = b + 3; + T f = (T) (p + a); + T g = (T) (p + b); + return f - g; +} + +T +f3 (char *p, size_t a, size_t b) +{ + size_t c = b + 1; + char *d = p + 2; + size_t e = a + 3; + T f = (T) (p + a); + T g = (T) (p + b); + return f - g; +} + +T +f4 (char *p, size_t a) +{ + char *c = p + 1; + size_t d = a + 2; + T f = (T) (p + a); + T g = (T) p; + return f - g; +} + +T +f5 (char *p, size_t a) +{ + size_t c = a + 1; + char *d = p + 2; + T f = (T) (p + a); + T g = (T) p; + return f - g; +} + +T +f6 (char *p, size_t a) +{ + char *c = p + 1; + size_t d = a + 2; + T f = (T) p; + T g = (T) (p + a); + return f - g; +} + +T +f7 (char *p, size_t a) +{ + size_t c = a + 1; + char *d = p + 2; + T f = (T) p; + T g = (T) (p + a); + return f - g; +}