[AArch64] Use SVE MLA, MLS, MAD and MSB for conditional arithmetic

[AArch64] Use SVE MLA, MLS, MAD and MSB for conditional arithmetic

This patch uses predicated MLA, MLS, MAD and MSB to implement
conditional "FMA"s on integers.  This also requires providing
the unpredicated optabs (fma and fnma) since otherwise
tree-ssa-math-opts.c won't try to use the conditional forms.

We still want to use shifts and adds in preference to multiplications,
so the patch makes the optab expanders check for that.

The tests cover floating-point types too, which are already handled,
and which were already tested to some extent by gcc.dg/vect.

2019-08-15  Richard Sandiford  <richard.sandiford@arm.com>
	    Kugan Vivekanandarajah  <kugan.vivekanandarajah@linaro.org>

gcc/
	* config/aarch64/aarch64-protos.h (aarch64_prepare_sve_int_fma)
	(aarch64_prepare_sve_cond_int_fma): Declare.
	* config/aarch64/aarch64.c (aarch64_convert_mult_to_shift)
	(aarch64_prepare_sve_int_fma): New functions.
	(aarch64_prepare_sve_cond_int_fma): Likewise.
	* config/aarch64/aarch64-sve.md
	(cond_<SVE_INT_BINARY:optab><SVE_I:mode>): Add a "@" marker.
	(fma<SVE_I:mode>4, cond_fma<SVE_I:mode>, *cond_fma<SVE_I:mode>_2)
	(*cond_fma<SVE_I:mode>_4, *cond_fma<SVE_I:mode>_any, fnma<SVE_I:mode>4)
	(cond_fnma<SVE_I:mode>, *cond_fnma<SVE_I:mode>_2)
	(*cond_fnma<SVE_I:mode>_4, *cond_fnma<SVE_I:mode>_any): New patterns.
	(*madd<mode>): Rename to...
	(*fma<mode>4): ...this.
	(*msub<mode>): Rename to...
	(*fnma<mode>4): ...this.

gcc/testsuite/
	* gcc.target/aarch64/sve/cond_mla_1.c: New test.
	* gcc.target/aarch64/sve/cond_mla_1_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_mla_2.c: Likewise.
	* gcc.target/aarch64/sve/cond_mla_2_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_mla_3.c: Likewise.
	* gcc.target/aarch64/sve/cond_mla_3_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_mla_4.c: Likewise.
	* gcc.target/aarch64/sve/cond_mla_4_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_mla_5.c: Likewise.
	* gcc.target/aarch64/sve/cond_mla_5_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_mla_6.c: Likewise.
	* gcc.target/aarch64/sve/cond_mla_6_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_mla_7.c: Likewise.
	* gcc.target/aarch64/sve/cond_mla_7_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_mla_8.c: Likewise.
	* gcc.target/aarch64/sve/cond_mla_8_run.c: Likewise.

Co-Authored-By: Kugan Vivekanandarajah <kuganv@linaro.org>
From-SVN: r274509