From a72610d4320925787d635cb4ddb8a40967e05bc3 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Fri, 15 Dec 2017 15:36:26 +0100 Subject: [PATCH] re PR sanitizer/81281 (UBSAN: false positive, dropped promotion to long type.) PR sanitizer/81281 * match.pd ((T)(P + A) - (T)P -> (T) A): Use @@0 instead of @0 and convert? on @0 instead of convert. Check type of @1, not @0. ((T)P - (T)(P + A) -> -(T) A): Use @@0 instead of @0 and convert? on @0 instead of convert. Check type of @1, not @0. ((T)(P + A) - (T)(P + B) -> (T)A - (T)B): Use @@0 instead of @0, only optimize if either both @1 and @2 types are narrower precision, or both are wider or equal precision, and in the former case only if both have undefined overflow. * gcc.dg/pr81281-3.c: New test. From-SVN: r255696 --- gcc/ChangeLog | 12 ++++ gcc/match.pd | 45 +++++++------ gcc/testsuite/ChangeLog | 5 ++ gcc/testsuite/gcc.dg/pr81281-3.c | 105 +++++++++++++++++++++++++++++++ 4 files changed, 147 insertions(+), 20 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/pr81281-3.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 3282f489370..8d655acf2c8 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,15 @@ +2017-12-15 Jakub Jelinek + + PR sanitizer/81281 + * match.pd ((T)(P + A) - (T)P -> (T) A): Use @@0 instead of @0 and + convert? on @0 instead of convert. Check type of @1, not @0. + ((T)P - (T)(P + A) -> -(T) A): Use @@0 instead of @0 and + convert? on @0 instead of convert. Check type of @1, not @0. + ((T)(P + A) - (T)(P + B) -> (T)A - (T)B): Use @@0 instead of @0, + only optimize if either both @1 and @2 types are narrower + precision, or both are wider or equal precision, and in the former + case only if both have undefined overflow. + 2017-12-15 Richard Biener PR lto/83388 diff --git a/gcc/match.pd b/gcc/match.pd index 0a4ff6bb8df..3943aceb059 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -1784,8 +1784,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) /* (T)(P + A) - (T)P -> (T) A */ (simplify - (minus (convert (plus:c @0 @1)) - (convert @0)) + (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 @@ -1794,8 +1794,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) 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)))) + || (INTEGRAL_TYPE_P (TREE_TYPE (@1)) + && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@1)))) (convert @1))) (simplify (minus (convert (pointer_plus @@0 @1)) @@ -1818,8 +1818,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) /* (T)P - (T)(P + A) -> -(T) A */ (simplify - (minus (convert @0) - (convert (plus:c @0 @1))) + (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))) @@ -1833,8 +1833,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) 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)))) + || (INTEGRAL_TYPE_P (TREE_TYPE (@1)) + && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@1)))) (negate (convert @1))))) (simplify (minus (convert @0) @@ -1862,23 +1862,28 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) /* (T)(P + A) - (T)(P + B) -> (T)A - (T)B */ (simplify - (minus (convert (plus:c @0 @1)) + (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))) + && element_precision (type) <= element_precision (TREE_TYPE (@1)) + && element_precision (type) <= element_precision (TREE_TYPE (@2))) (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 - 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)))) + (if (((element_precision (type) <= element_precision (TREE_TYPE (@1))) + == (element_precision (type) <= element_precision (TREE_TYPE (@2)))) + && (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 (@1)) + && INTEGRAL_TYPE_P (TREE_TYPE (@2)) + && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@1)) + && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@2))))) (minus (convert @1) (convert @2))))) (simplify (minus (convert (pointer_plus @@0 @1)) diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 176a7b9c44f..e1196919a3c 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2017-12-15 Jakub Jelinek + + PR sanitizer/81281 + * gcc.dg/pr81281-3.c: New test. + 2017-12-15 Justin Squirek * gnat.dg/aliasing4.adb: New testcase. diff --git a/gcc/testsuite/gcc.dg/pr81281-3.c b/gcc/testsuite/gcc.dg/pr81281-3.c new file mode 100644 index 00000000000..e4918358482 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr81281-3.c @@ -0,0 +1,105 @@ +/* PR sanitizer/81281 */ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-optimized" } */ +/* { dg-final { scan-tree-dump-not "\[+=-] \?123\[ ;]" "optimized" } } */ + +#ifdef __SIZEOF_INT128__ +__int128 +f1 (int a, long long b) +{ + __int128 f = 123 + a; + __int128 g = 123 + b; + return f - g; +} +#endif + +signed char +f2 (int a, long long b) +{ + signed char f = 123 + a; + signed char g = 123 + b; + return f - g; +} + +signed char +f3 (unsigned int a, unsigned long long b) +{ + signed char f = 123 + a; + signed char g = 123 + b; + return f - g; +} + +unsigned char +f4 (unsigned int a, unsigned long long b) +{ + unsigned char f = 123 + a; + unsigned char g = 123 + b; + return f - g; +} + +/* This isn't optimized yet. */ +#if 0 +long long +f5 (int a) +{ + long long f = 123 + a; + long long g = 123; + return f - g; +} +#endif + +signed char +f6 (long long a) +{ + signed char f = 123 + a; + signed char g = 123; + return f - g; +} + +signed char +f7 (unsigned int a) +{ + signed char f = 123 + a; + signed char g = 123; + return f - g; +} + +unsigned char +f8 (unsigned long int a) +{ + unsigned char f = 123 + a; + unsigned char g = 123; + return f - g; +} + +long long +f9 (int a) +{ + long long f = 123; + long long g = 123 + a; + return f - g; +} + +signed char +f10 (long long a) +{ + signed char f = 123; + signed char g = 123 + a; + return f - g; +} + +signed char +f11 (unsigned int a) +{ + signed char f = 123; + signed char g = 123 + a; + return f - g; +} + +unsigned char +f12 (unsigned long int a) +{ + unsigned char f = 123; + unsigned char g = 123 + a; + return f - g; +} -- 2.30.2