On Tue, Jun 23, 2015 at 10:22:35AM +0200, Richard Biener wrote: > Who says you can't do bitwise ops on them? I can't see that being > enforced in the GIMPLE checking in tree-cfg.c. Yes, there is no > such thing as a "saturating" bitwise and but bitwise and should > just work fine. > > You can check with a arm cross what the C FE does when you use > bitwise ops but I believe the regular and/ior md patterns work > just fine (there are no special modes/registers but they seem > to be shared with regular registers, just special operations > are available).
Ok ;). Applied the following then. 2015-06-23 Marek Polacek <pola...@redhat.com> * match.pd ((x + y) - (x | y) -> x & y, (x + y) - (x & y) -> x | y): New patterns. * gcc.dg/fold-minus-4.c: New test. * gcc.dg/fold-minus-5.c: New test. * c-c++-common/ubsan/overflow-add-5.c: New test. diff --git gcc/match.pd gcc/match.pd index badb80a..9c88e3e 100644 --- gcc/match.pd +++ gcc/match.pd @@ -343,6 +343,20 @@ along with GCC; see the file COPYING3. If not see (plus:c (bit_and @0 @1) (bit_ior @0 @1)) (plus @0 @1)) +/* (x + y) - (x | y) -> x & y */ +(simplify + (minus (plus @0 @1) (bit_ior @0 @1)) + (if (!TYPE_OVERFLOW_SANITIZED (type) && !TYPE_OVERFLOW_TRAPS (type) + && !TYPE_SATURATING (type)) + (bit_and @0 @1))) + +/* (x + y) - (x & y) -> x | y */ +(simplify + (minus (plus @0 @1) (bit_and @0 @1)) + (if (!TYPE_OVERFLOW_SANITIZED (type) && !TYPE_OVERFLOW_TRAPS (type) + && !TYPE_SATURATING (type)) + (bit_ior @0 @1))) + /* (x | y) - (x ^ y) -> x & y */ (simplify (minus (bit_ior @0 @1) (bit_xor @0 @1)) diff --git gcc/testsuite/c-c++-common/ubsan/overflow-add-5.c gcc/testsuite/c-c++-common/ubsan/overflow-add-5.c index e69de29..905a60a 100644 --- gcc/testsuite/c-c++-common/ubsan/overflow-add-5.c +++ gcc/testsuite/c-c++-common/ubsan/overflow-add-5.c @@ -0,0 +1,30 @@ +/* { dg-do run } */ +/* { dg-options "-fsanitize=signed-integer-overflow" } */ + +int __attribute__ ((noinline)) +foo (int i, int j) +{ + return (i + j) - (i | j); +} + +/* { dg-output "signed integer overflow: 2147483647 \\+ 1 cannot be represented in type 'int'\[^\n\r]*(\n|\r\n|\r)" } */ +/* { dg-output "\[^\n\r]*signed integer overflow: -2147483648 - 2147483647 cannot be represented in type 'int'\[^\n\r]*(\n|\r\n|\r)" } */ + +int __attribute__ ((noinline)) +bar (int i, int j) +{ + return (i + j) - (i & j); +} + +/* { dg-output "\[^\n\r]*signed integer overflow: 2147483647 \\+ 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'" } */ + +int +main () +{ + int r = foo (__INT_MAX__, 1); + asm volatile ("" : "+g" (r)); + r = bar (__INT_MAX__, 1); + asm volatile ("" : "+g" (r)); + return 0; +} diff --git gcc/testsuite/gcc.dg/fold-minus-4.c gcc/testsuite/gcc.dg/fold-minus-4.c index e69de29..2d76b4f 100644 --- gcc/testsuite/gcc.dg/fold-minus-4.c +++ gcc/testsuite/gcc.dg/fold-minus-4.c @@ -0,0 +1,37 @@ +/* { dg-do compile } */ +/* { dg-options "-O -fdump-tree-cddce1" } */ + +int +fn1 (int a, int b) +{ + int tem1 = a + b; + int tem2 = a & b; + return tem1 - tem2; +} + +int +fn2 (int a, int b) +{ + int tem1 = b + a; + int tem2 = a & b; + return tem1 - tem2; +} + +int +fn3 (int a, int b) +{ + int tem1 = a + b; + int tem2 = b & a; + return tem1 - tem2; +} + +int +fn4 (int a, int b) +{ + int tem1 = b + a; + int tem2 = b & a; + return tem1 - tem2; +} + +/* { dg-final { scan-tree-dump-not " & " "cddce1" } } */ +/* { dg-final { scan-tree-dump-not " \\+ " "cddce1" } } */ diff --git gcc/testsuite/gcc.dg/fold-minus-5.c gcc/testsuite/gcc.dg/fold-minus-5.c index e69de29..a31e1cc 100644 --- gcc/testsuite/gcc.dg/fold-minus-5.c +++ gcc/testsuite/gcc.dg/fold-minus-5.c @@ -0,0 +1,37 @@ +/* { dg-do compile } */ +/* { dg-options "-O -fdump-tree-cddce1" } */ + +int +fn1 (int a, int b) +{ + int tem1 = a + b; + int tem2 = a | b; + return tem1 - tem2; +} + +int +fn2 (int a, int b) +{ + int tem1 = b + a; + int tem2 = a | b; + return tem1 - tem2; +} + +int +fn3 (int a, int b) +{ + int tem1 = a + b; + int tem2 = b | a; + return tem1 - tem2; +} + +int +fn4 (int a, int b) +{ + int tem1 = b + a; + int tem2 = b | a; + return tem1 - tem2; +} + +/* { dg-final { scan-tree-dump-not " \\+ " "cddce1" } } */ +/* { dg-final { scan-tree-dump-not " \\| " "cddce1" } } */ Marek