[ARM] Fix Thumb-1 ldm (PR89190)

[ARM] Fix Thumb-1 ldm (PR89190)

This patch fixes an ICE in the Thumb-1 LDM peepholer.  Thumb-1 LDMs
always update the base register except if the base is loaded.
The current implementation rejects LDMs where the base is not dead,
however this doesn't exclude the case where the base is loaded as
well as dead.  Fix this by explicitly checking whether the base is
loaded.  Also enable LDMs which load the first register.

    gcc/
	PR target/89190
	* config/arm/arm.c (ldm_stm_operation_p) Set
	addr_reg_in_reglist correctly for first register.
	(load_multiple_sequence): Remove dead base check.
	(gen_ldm_seq): Correctly set write_back for Thumb-1.

    testsuite/
	PR target/89190
	* gcc.target/arm/pr89190.c: New test.

From-SVN: r268848