| Message ID | 1421837394-7619-2-git-send-email-rv@rasmusvillemoes.dk |
|---|---|
| State | New |
| Headers | show |
On Wed, Jan 21, 2015 at 11:49 AM, Rasmus Villemoes <rv@rasmusvillemoes.dk> wrote: > gcc.dg/20150120-1.c: New test > > Rounding an integer to the next even integer is sometimes written x += > x & 1. The equivalent x = (x+1)&~1 usually uses one less register, and > in practical cases only the new value of x will be used (making it > unlikely that the subexpression x&1 has any uses). Now that we are in stage1 again You are missig a ChangeLog entry and fail to state how you tested the patch. Otherwise the patch looks ok. Thanks, Richard. > Signed-off-by: Rasmus Villemoes <rv@rasmusvillemoes.dk> > --- > gcc/match.pd | 6 +++++ > gcc/testsuite/gcc.dg/20150120-1.c | 51 +++++++++++++++++++++++++++++++++++++++ > 2 files changed, 57 insertions(+) > create mode 100644 gcc/testsuite/gcc.dg/20150120-1.c > > diff --git gcc/match.pd gcc/match.pd > index 81c4ee6..ecefcfb 100644 > --- gcc/match.pd > +++ gcc/match.pd > @@ -255,6 +255,12 @@ along with GCC; see the file COPYING3. If not see > (bitop @0 @0) > (non_lvalue @0))) > > +/* x + (x & 1) -> (x + 1) & ~1 */ > +(simplify > + (plus:c @0 (bit_and@2 @0 integer_onep@1)) > + (if (TREE_CODE (@2) != SSA_NAME || has_single_use (@2)) > + (bit_and (plus @0 @1) (bit_not @1)))) > + > (simplify > (abs (negate @0)) > (abs @0)) > diff --git gcc/testsuite/gcc.dg/20150120-1.c gcc/testsuite/gcc.dg/20150120-1.c > new file mode 100644 > index 0000000..18906c4 > --- /dev/null > +++ gcc/testsuite/gcc.dg/20150120-1.c > @@ -0,0 +1,51 @@ > +/* { dg-do compile } */ > +/* { dg-options "-O2 -fdump-tree-original" } */ > + > +/* x + (x & 1) -> (x + 1) & ~1 */ > +int > +fn1 (int x) > +{ > + return x + (x & 1); > +} > +int > +fn2 (int x) > +{ > + return (x & 1) + x; > +} > +int > +fn3 (int x) > +{ > + return x + (1 & x); > +} > +int > +fn4 (int x) > +{ > + return (1 & x) + x; > +} > +unsigned int > +fn5 (unsigned int x) > +{ > + return x + (x & 1); > +} > +unsigned int > +fn6 (unsigned int x) > +{ > + return (x & 1) + x; > +} > +unsigned int > +fn7 (unsigned int x) > +{ > + return x + (x % 2); > +} > +unsigned int > +fn8 (unsigned int x) > +{ > + return (x % 2) + x; > +} > +unsigned int > +fn9 (unsigned int x) > +{ > + return (1LL & x) + x; > +} > + > +/* { dg-final { scan-tree-dump-times "x \\+ 1" 9 "original" } } */ > -- > 2.1.3 >
On 01/21/2015 03:49 AM, Rasmus Villemoes wrote: > gcc.dg/20150120-1.c: New test > > Rounding an integer to the next even integer is sometimes written x += > x & 1. The equivalent x = (x+1)&~1 usually uses one less register, and > in practical cases only the new value of x will be used (making it > unlikely that the subexpression x&1 has any uses). I bootstrapped and regression tested this on x86_64-linux-gnu, created the appropriate ChangeLogs and installed the patch on the trunk. Jeff
diff --git gcc/match.pd gcc/match.pd index 81c4ee6..ecefcfb 100644 --- gcc/match.pd +++ gcc/match.pd @@ -255,6 +255,12 @@ along with GCC; see the file COPYING3. If not see (bitop @0 @0) (non_lvalue @0))) +/* x + (x & 1) -> (x + 1) & ~1 */ +(simplify + (plus:c @0 (bit_and@2 @0 integer_onep@1)) + (if (TREE_CODE (@2) != SSA_NAME || has_single_use (@2)) + (bit_and (plus @0 @1) (bit_not @1)))) + (simplify (abs (negate @0)) (abs @0)) diff --git gcc/testsuite/gcc.dg/20150120-1.c gcc/testsuite/gcc.dg/20150120-1.c new file mode 100644 index 0000000..18906c4 --- /dev/null +++ gcc/testsuite/gcc.dg/20150120-1.c @@ -0,0 +1,51 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-original" } */ + +/* x + (x & 1) -> (x + 1) & ~1 */ +int +fn1 (int x) +{ + return x + (x & 1); +} +int +fn2 (int x) +{ + return (x & 1) + x; +} +int +fn3 (int x) +{ + return x + (1 & x); +} +int +fn4 (int x) +{ + return (1 & x) + x; +} +unsigned int +fn5 (unsigned int x) +{ + return x + (x & 1); +} +unsigned int +fn6 (unsigned int x) +{ + return (x & 1) + x; +} +unsigned int +fn7 (unsigned int x) +{ + return x + (x % 2); +} +unsigned int +fn8 (unsigned int x) +{ + return (x % 2) + x; +} +unsigned int +fn9 (unsigned int x) +{ + return (1LL & x) + x; +} + +/* { dg-final { scan-tree-dump-times "x \\+ 1" 9 "original" } } */
gcc.dg/20150120-1.c: New test Rounding an integer to the next even integer is sometimes written x += x & 1. The equivalent x = (x+1)&~1 usually uses one less register, and in practical cases only the new value of x will be used (making it unlikely that the subexpression x&1 has any uses). Signed-off-by: Rasmus Villemoes <rv@rasmusvillemoes.dk> --- gcc/match.pd | 6 +++++ gcc/testsuite/gcc.dg/20150120-1.c | 51 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 57 insertions(+) create mode 100644 gcc/testsuite/gcc.dg/20150120-1.c