This patch is for PR target/91816

This patch is for PR target/91816

This is a patch for an issue where the compiler was generating a conditional
branch in Thumb2, which was too far for b{cond} to handle.

This was originally reported at binutils:
https://sourceware.org/bugzilla/show_bug.cgi?id=24991

And then raised for GCC:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91816

As can be seen here:

http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0489c/Cihfddaf.html

the range of a 32-bit Thumb B{cond} is +/-1MB.

This is now checked for in arm.md and an unconditional branch is generated if
the jump would be greater than 1MB.

gcc/ChangeLog

2020-02-03  Stam Markianos-Wright  <stam.markianos-wright@arm.com>

	PR target/91816
	* config/arm/arm-protos.h: New function arm_gen_far_branch prototype.
	* config/arm/arm.c (arm_gen_far_branch): New function
	arm_gen_far_branch.
	* config/arm/arm.md: Update b<cond> for Thumb2 range checks.

gcc/testsuite/ChangeLog

2020-02-03  Stam Markianos-Wright  <stam.markianos-wright@arm.com>

	PR target/91816
	* gcc.target/arm/pr91816.c: New test.