diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/match.pd | 10 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 3 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.target/i386/pr94956.c | 28 |
4 files changed, 45 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index eb4924a..5bad3ff 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,9 @@ 2020-05-08 Jakub Jelinek <jakub@redhat.com> + PR tree-optimization/94956 + * match.pd (FFS): Optimize __builtin_ffs* of non-zero argument into + __builtin_ctz* + 1 if direct IFN_CTZ is supported. + PR tree-optimization/94913 * match.pd (A - B + -1 >= A to B >= A): New simplification. (A - B > A to A < B): Don't test TYPE_OVERFLOW_WRAPS which is always diff --git a/gcc/match.pd b/gcc/match.pd index cfe9697..892df1e 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -5986,6 +5986,16 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) && direct_internal_fn_supported_p (IFN_POPCOUNT, type, OPTIMIZE_FOR_BOTH)) (convert (IFN_POPCOUNT:type @0))))) + +/* __builtin_ffs needs to deal on many targets with the possible zero + argument. If we know the argument is always non-zero, __builtin_ctz + 1 + should lead to better code. */ +(simplify + (FFS tree_expr_nonzero_p@0) + (if (INTEGRAL_TYPE_P (TREE_TYPE (@0)) + && direct_internal_fn_supported_p (IFN_CTZ, TREE_TYPE (@0), + OPTIMIZE_FOR_SPEED)) + (plus (CTZ:type @0) { build_one_cst (type); }))) #endif /* Simplify: diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 43e226e..e8c54c7 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,8 @@ 2020-05-08 Jakub Jelinek <jakub@redhat.com> + PR tree-optimization/94956 + * gcc.target/i386/pr94956.c: New test. + PR tree-optimization/94913 * gcc.dg/tree-ssa/pr94913.c: New test. diff --git a/gcc/testsuite/gcc.target/i386/pr94956.c b/gcc/testsuite/gcc.target/i386/pr94956.c new file mode 100644 index 0000000..cc27b45 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr94956.c @@ -0,0 +1,28 @@ +/* PR tree-optimization/94956 */ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ +/* { dg-final { scan-assembler-not "\tcmovne\t" } } */ +/* { dg-final { scan-assembler-not "\tsete\t" } } */ + +int +foo (unsigned x) +{ + if (x == 0) __builtin_unreachable (); + return __builtin_ffs (x) - 1; +} + +int +bar (unsigned long x) +{ + if (x == 0) __builtin_unreachable (); + return __builtin_ffsl (x) - 1; +} + +#ifdef __x86_64__ +int +baz (unsigned long long x) +{ + if (x == 0) __builtin_unreachable (); + return __builtin_ffsll (x) - 1; +} +#endif |