[PATCH][ARM] use vsel instruction for floating point conditional moves in ARMv8

["Kyrylo Tkachov" <kyrylo dot tkachov at arm dot com>]

Hi all,
This patch uses the new ARMv8 AArch32 vsel instruction to implement
conditional moves of floating point numbers.
For example, an instruction of the form:
	vsel<cond>.f32  s0, s1, s2
means
	s0 := cond ? s1 : s2

This can be useful, among other places, in Thumb2 because it doesn't require
an enclosing IT block.
A small catch: The condition code used in vsel can only be one of {GE, GT,
EQ, VS}. If we want to use their negations {LT, LE, NE, VC} we just flip the
source operands.
A new predicate is introduced that checks that the comparison yields an ARM
condition code in the set {GE, GT, EQ, VS, LT, LE, NE, VC}.

New compilation tests are added. They pass on a model and no new regressions
on arm-none-eabi with qemu.

Ok for trunk?

Thanks,
Kyrill

gcc/ChangeLog

2013-01-30  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>

	* config/arm/arm.md (f_sels, f_seld): New types.
	(*cmov<mode>): New pattern.
	* config/arm/predicates.md (arm_vsel_comparison_operator): New
predicate.	


gcc/testsuite/ChangeLog

2013-01-30  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>

	* gcc.target/arm/vseleqdf.c: New test.
	* gcc.target/arm/vseleqsf.c: Likewise.
	* gcc.target/arm/vselgedf.c: Likewise.
	* gcc.target/arm/vselgesf.c: Likewise.
	* gcc.target/arm/vselgtdf.c: Likewise.
	* gcc.target/arm/vselgtsf.c: Likewise.
	* gcc.target/arm/vselledf.c: Likewise.
	* gcc.target/arm/vsellesf.c: Likewise.
	* gcc.target/arm/vselltdf.c: Likewise.
	* gcc.target/arm/vselltsf.c: Likewise.
	* gcc.target/arm/vselnedf.c: Likewise.
	* gcc.target/arm/vselnesf.c: Likewise.
	* gcc.target/arm/vselvcdf.c: Likewise.
	* gcc.target/arm/vselvcsf.c: Likewise.
	* gcc.target/arm/vselvsdf.c: Likewise.
	* gcc.target/arm/vselvssf.c: Likewise.

Attachment: vsel_full.txt
Description: Text document