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[0/9] Add more folds related to exact division

Message ID 20241018111806.4026759-1-richard.sandiford@arm.com
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Series Add more folds related to exact division | expand

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Richard Sandiford Oct. 18, 2024, 11:17 a.m. UTC 
This series adds some more rules for identifying and folding
exact divisions, including shifts right by C when the low C
bits are known to be zero.  It also extends some existing rules
to handle poly_ints.

The original motivation was to improve address arithmetic for
some upcoming SVE testcases.

Bootstrapped & regression-tested on aarch64-linux-gnu.  OK to install?

Richard


Richard Sandiford (9):
  Make more places handle exact_div like trunc_div
  Use get_nonzero_bits to simplify trunc_div to exact_div
  Simplify X /[ex] Y cmp Z -> X cmp (Y * Z)
  Simplify (X /[ex] C1) * (C1 * C2) -> X * C2
  Generalise ((X /[ex] A) +- B) * A -> X +- A * B rule
  Try to simplify (X >> C1) << (C1 + C2) -> X << C2
  Handle POLY_INT_CSTs in get_nonzero_bits
  Try to simplify (X >> C1) * (C2 << C1) -> X * C2
  Record nonzero bits in the irange_bitmask of POLY_INT_CSTs

 gcc/match.pd                                  | 164 +++++++++++++-----
 gcc/range-op-mixed.h                          |   9 +-
 gcc/range-op.cc                               |  19 +-
 gcc/range-op.h                                |  31 +++-
 gcc/testsuite/gcc.dg/tree-ssa/cmpexactdiv-6.c |  29 ++++
 gcc/testsuite/gcc.dg/tree-ssa/cmpexactdiv-7.c |  21 +++
 gcc/testsuite/gcc.dg/tree-ssa/cmpexactdiv-8.c |  20 +++
 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-1.c |  23 +++
 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-2.c |  19 ++
 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-3.c |  21 +++
 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-4.c |  14 ++
 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-5.c |  29 ++++
 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-6.c |  59 +++++++
 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-7.c |  22 +++
 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-8.c |  20 +++
 gcc/testsuite/gcc.dg/tree-ssa/shifts-1.c      |  61 +++++++
 gcc/testsuite/gcc.dg/tree-ssa/shifts-2.c      |  21 +++
 gcc/testsuite/gcc.dg/tree-ssa/shifts-3.c      |  65 +++++++
 gcc/testsuite/gcc.dg/tree-ssa/shifts-4.c      |  23 +++
 .../gcc.target/aarch64/sve/cnt_fold_1.c       | 110 ++++++++++++
 .../gcc.target/aarch64/sve/cnt_fold_2.c       |  55 ++++++
 .../gcc.target/aarch64/sve/cnt_fold_3.c       |  40 +++++
 .../gcc.target/aarch64/sve/cnt_fold_4.c       |  61 +++++++
 .../gcc.target/aarch64/sve/cnt_fold_5.c       |  38 ++++
 .../gcc.target/aarch64/sve/cnt_fold_6.c       |  75 ++++++++
 gcc/tree-ssa-loop-ivopts.cc                   |   2 +
 gcc/tree-ssa-loop-niter.cc                    |   2 +-
 gcc/tree-ssanames.cc                          |   3 +
 gcc/tree.h                                    |  13 ++
 gcc/value-query.cc                            |   7 +
 30 files changed, 1018 insertions(+), 58 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/cmpexactdiv-6.c
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/cmpexactdiv-7.c
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/cmpexactdiv-8.c
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-1.c
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-2.c
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-3.c
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-4.c
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-5.c
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-6.c
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-7.c
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/mulexactdiv-8.c
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/shifts-1.c
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/shifts-2.c
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/shifts-3.c
 create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/shifts-4.c
 create mode 100644 gcc/testsuite/gcc.target/aarch64/sve/cnt_fold_1.c
 create mode 100644 gcc/testsuite/gcc.target/aarch64/sve/cnt_fold_2.c
 create mode 100644 gcc/testsuite/gcc.target/aarch64/sve/cnt_fold_3.c
 create mode 100644 gcc/testsuite/gcc.target/aarch64/sve/cnt_fold_4.c
 create mode 100644 gcc/testsuite/gcc.target/aarch64/sve/cnt_fold_5.c
 create mode 100644 gcc/testsuite/gcc.target/aarch64/sve/cnt_fold_6.c