Add support for conditional shifts

This patch adds support for IFN_COND shifts left and shifts right.
This is mostly mechanical, but since we try to handle conditional
operations in the same way as unconditional operations in match.pd,
we need to support IFN_COND shifts by scalars as well as vectors.
E.g.:

   IFN_COND_SHL (cond, a, { 1, 1, ... }, fallback)

and:

   IFN_COND_SHL (cond, a, 1, fallback)

are the same operation, with:

   (for shiftrotate (lrotate rrotate lshift rshift)
    ...
    /* Prefer vector1 << scalar to vector1 << vector2
       if vector2 is uniform.  */
    (for vec (VECTOR_CST CONSTRUCTOR)
     (simplify
      (shiftrotate @0 vec@1)
      (with { tree tem = uniform_vector_p (@1); }
       (if (tem)
	(shiftrotate @0 { tem; }))))))

preferring the latter.  The patch copes with this by extending
create_convert_operand_from to handle scalar-to-vector conversions.

2019-08-15  Richard Sandiford  <richard.sandiford@arm.com>
	    Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>

gcc/
	* internal-fn.def (IFN_COND_SHL, IFN_COND_SHR): New internal functions.
	* internal-fn.c (FOR_EACH_CODE_MAPPING): Handle shifts.
	* match.pd (UNCOND_BINARY, COND_BINARY): Likewise.
	* optabs.def (cond_ashl_optab, cond_ashr_optab, cond_lshr_optab): New
	optabs.
	* optabs.h (create_convert_operand_from): Expand comment.
	* optabs.c (maybe_legitimize_operand): Allow implicit broadcasts
	when mapping scalar rtxes to vector operands.
	* config/aarch64/iterators.md (SVE_INT_BINARY): Add ashift,
	ashiftrt and lshiftrt.
	(sve_int_op, sve_int_op_rev, sve_pred_int_rhs2_operand): Handle them.
	* config/aarch64/aarch64-sve.md (*cond_<optab><mode>_2_const)
	(*cond_<optab><mode>_any_const): New patterns.

gcc/testsuite/
	* gcc.target/aarch64/sve/cond_shift_1.c: New test.
	* gcc.target/aarch64/sve/cond_shift_1_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_2.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_2_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_3.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_3_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_4.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_4_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_5.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_5_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_6.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_6_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_7.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_7_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_8.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_8_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_9.c: Likewise.
	* gcc.target/aarch64/sve/cond_shift_9_run.c: Likewise.

Co-Authored-By: Prathamesh Kulkarni <prathamesh.kulkarni@linaro.org>

From-SVN: r274505

1 files changed, 5 insertions, 1 deletions

diff --git a/gcc/optabs.h b/gcc/optabs.h
index 0654107..897bb5d 100644
--- a/gcc/optabs.h
+++ b/gcc/optabs.h
@@ -129,7 +129,11 @@ create_convert_operand_to (class expand_operand *op, rtx value,
 /* Make OP describe an input operand that should have the same value
    as VALUE, after any mode conversion that the backend might request.
    If VALUE is a CONST_INT, it should be treated as having mode MODE.
-   UNSIGNED_P says whether VALUE is unsigned.  */
+   UNSIGNED_P says whether VALUE is unsigned.
+
+   The conversion of VALUE can include a combination of numerical
+   conversion (as for convert_modes) and duplicating a scalar to fill
+   a vector (if VALUE is a scalar but the operand is a vector).  */
 
 static inline void
 create_convert_operand_from (class expand_operand *op, rtx value,