[PATCH][GCC][AArch64] Inline calls to lrint when possible

[Tamar Christina]

Hi All,

This patch allows the inlining of lrint when -fno-math-errno
assuming that errno does not need to be set when the rounded value
is not representable as a long.

The case

void f(double *a, long *b, double x)
{
	*a = __builtin_rint(x);
	*b = __builtin_lrint(x);
}

now generates with -fno-math-errno:

f:
	frintx	d0, d0
	fcvtzs	x2, d0
	str	d0, [x0]
	str	x2, [x1]
	ret

When the flag is not used the same function call is emitted as before:

f:
	stp	x29, x30, [sp, -32]!
	frintx	d1, d0
	add	x29, sp, 0
	str	x19, [sp, 16]
	mov	x19, x1
	str	d1, [x0]
	bl	lrint
	str	x0, [x19]
	ldr	x19, [sp, 16]
	ldp	x29, x30, [sp], 32
	ret

Bootstrapped and regtested on aarch64-none-linux-gnu and no regressions.
The patch also has no regressions on Spec2006.

Ok for trunk?

gcc/
2017-06-07  Tamar Christina  <tamar.christina@arm.com>

	* config/aarch64/aarch64.md (lrint<GPF:mode><GPI:mode>2): New.

gcc/testsuite/
2017-06-07  Tamar Christina  <tamar.christina@arm.com>

	* gcc.target/aarch64/lrint-matherr.h: New.
	* gcc.target/aarch64/inline-lrint_1.c: New.
	* gcc.target/aarch64/inline-lrint_2.c: New.
	* gcc.target/aarch64/no-inline-lrint_1.c: New.
	* gcc.target/aarch64/no-inline-lrint_2.c: New.
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