This patch adds a new "poly_int" class to represent polynomial integers of the form:
C0 + C1*X1 + C2*X2 ... + Cn*Xn
It also adds poly_int-based typedefs for offsets and sizes of various
precisions. In these typedefs, the Ci coefficients are compile-time
constants and the Xi indeterminates are run-time invariants. The number
of coefficients is controlled by the target and is initially 1 for all
ports.
Most routines can handle general coefficient counts, but for now a few
are specific to one or two coefficients. Support for other coefficient
counts can be added when needed.
The patch also adds a new macro, IN_TARGET_CODE, that can be
set to indicate that a TU contains target-specific rather than
target-independent code. When this macro is set and the number of
coefficients is 1, the poly-int.h classes define a conversion operator
to a constant. This allows most existing target code to work without
modification. The main exceptions are:
- values passed through ..., which need an explicit conversion to a
constant
- ?: expression in which one arm ends up being a polynomial and the
other remains a constant. In these cases it would be valid to convert
the constant to a polynomial and the polynomial to a constant, so a
cast is needed to break the ambiguity.
The patch also adds a new target hook to return the estimated
value of a polynomial for costing purposes.
The patch also adds operator<< on wide_ints (it was already defined
for offset_int and widest_int). I think this was originally excluded
because >> is ambiguous for wide_int, but << is useful for converting
bytes to bits, etc., so is worth defining on its own. The patch also
adds operator% and operator/ for offset_int and widest_int, since those
types are always signed. These changes allow the poly_int interface to
be more predictable.
I'd originally tried adding the tests as selftests, but that ended up
bloating cc1 by at least a third. It also took a while to build them
at -O2. The patch therefore uses plugin tests instead, where we can
force the tests to be built at -O0. They still run in negligible time
when built that way.
2017-10-23 Richard Sandiford <richard.sandif...@linaro.org>
Alan Hayward <alan.hayw...@arm.com>
David Sherwood <david.sherw...@arm.com>
gcc/
* poly-int.h: New file.
* poly-int-types.h: Likewise.
* coretypes.h: Include them.
(POLY_INT_CONVERSION): Define.
* target.def (estimated_poly_value): New hook.
* doc/tm.texi.in (TARGET_ESTIMATED_POLY_VALUE): New hook.
* doc/tm.texi: Regenerate.
* doc/poly-int.texi: New file.
* doc/gccint.texi: Include it.
* doc/rtl.texi: Describe restrictions on subreg modes.
* Makefile.in (TEXI_GCCINT_FILES): Add poly-int.texi.
* genmodes.c (NUM_POLY_INT_COEFFS): Provide a default definition.
(emit_insn_modes_h): Emit a definition of NUM_POLY_INT_COEFFS.
* targhooks.h (default_estimated_poly_value): Declare.
* targhooks.c (default_estimated_poly_value): New function.
* target.h (estimated_poly_value): Likewise.
* wide-int.h (WI_UNARY_RESULT): Use wi::binary_traits.
(wi::unary_traits): Delete.
(wi::binary_traits::signed_shift_result_type): Define for
offset_int << HOST_WIDE_INT, etc.
(generic_wide_int::operator <<=): Define for all types and use
wi::lshift instead of <<.
(wi::hwi_with_prec): Add a default constructor.
(wi::ints_for): New class.
(operator <<): Define for all wide-int types.
(operator /): New function.
(operator %): Likewise.
* selftest.h (ASSERT_MUST_EQ, ASSERT_MUST_EQ_AT, ASSERT_MAY_NE)
(ASSERT_MAY_NE_AT): New macros.
gcc/testsuite/
* gcc.dg/plugin/poly-int-tests.h,
gcc.dg/plugin/poly-int-test-1.c,
gcc.dg/plugin/poly-int-01_plugin.c,
gcc.dg/plugin/poly-int-02_plugin.c,
gcc.dg/plugin/poly-int-03_plugin.c,
gcc.dg/plugin/poly-int-04_plugin.c,
gcc.dg/plugin/poly-int-05_plugin.c,
gcc.dg/plugin/poly-int-06_plugin.c,
gcc.dg/plugin/poly-int-07_plugin.c: New tests.
* gcc.dg/plugin/plugin.exp: Run them.
poly-int.diff.bz2
Description: BZip2 compressed data
