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From: Andrew Pinski <pinskia@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc r14-4686] MATCH: [PR111432] Simplify `a & (x | CST)` to a when we know that (a & ~CST) == 0 Date: Tue, 17 Oct 2023 16:04:17 +0000 (GMT) [thread overview] Message-ID: <20231017160417.EBCEC3858C35@sourceware.org> (raw) https://gcc.gnu.org/g:b18d1cabe2f9cccc0cad697e1e0bfd2abebb85f9 commit r14-4686-gb18d1cabe2f9cccc0cad697e1e0bfd2abebb85f9 Author: Andrew Pinski <pinskia@gmail.com> Date: Fri Oct 13 13:27:18 2023 -0700 MATCH: [PR111432] Simplify `a & (x | CST)` to a when we know that (a & ~CST) == 0 This adds the simplification `a & (x | CST)` to a when we know that `(a & ~CST) == 0`. In a similar fashion as `a & CST` is handle. I looked into handling `a | (x & CST)` but that I don't see any decent simplifications happening. OK? Bootstrapped and tested on x86_linux-gnu with no regressions. PR tree-optimization/111432 gcc/ChangeLog: * match.pd (`a & (x | CST)`): New pattern. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/bitops-7.c: New test. Diff: --- gcc/match.pd | 8 ++++++++ gcc/testsuite/gcc.dg/tree-ssa/bitops-7.c | 24 ++++++++++++++++++++++++ 2 files changed, 32 insertions(+) diff --git a/gcc/match.pd b/gcc/match.pd index dbd554e2e7c1..067328a2a16b 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -1550,6 +1550,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (if (INTEGRAL_TYPE_P (TREE_TYPE (@0)) && wi::bit_and_not (get_nonzero_bits (@0), wi::to_wide (@1)) == 0) @0)) + +/* `a & (x | CST)` -> a if we know that (a & ~CST) == 0 */ +(simplify + (bit_and:c SSA_NAME@0 (bit_ior @1 INTEGER_CST@2)) + (if (INTEGRAL_TYPE_P (TREE_TYPE (@0)) + && wi::bit_and_not (get_nonzero_bits (@0), wi::to_wide (@2)) == 0) + @0)) + /* x | C -> C if we know that x & ~C == 0. */ (simplify (bit_ior SSA_NAME@0 INTEGER_CST@1) diff --git a/gcc/testsuite/gcc.dg/tree-ssa/bitops-7.c b/gcc/testsuite/gcc.dg/tree-ssa/bitops-7.c new file mode 100644 index 000000000000..7fb18db3a110 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/bitops-7.c @@ -0,0 +1,24 @@ +/* { dg-do compile } */ +/* { dg-options "-O1 -fdump-tree-optimized-raw" } */ +/* PR tree-optimization/111432 */ + +int +foo3(int c, int bb) +{ + if ((bb & ~3)!=0) __builtin_unreachable(); + return (bb & (c|3)); +} + +int +foo_bool(int c, _Bool bb) +{ + return (bb & (c|7)); +} + +/* Both of these functions should be able to remove the `IOR` and `AND` + as the only bits that are non-zero for bb is set on the other side + of the `AND`. + */ + +/* { dg-final { scan-tree-dump-not "bit_ior_expr, " "optimized" } } */ +/* { dg-final { scan-tree-dump-not "bit_and_expr, " "optimized" } } */
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