re PR target/29006 (Incorrect zeroing of unaligned 64-bit fields on MIPS targets)

re PR target/29006 (Incorrect zeroing of unaligned 64-bit fields on MIPS targets)

gcc/
	PR target/29006
	* config/mips/mips-protos.h (mips_mem_fits_mode_p): Declare.
	* config/mips/mips.c (mips_expand_unaligned_store): Use the mode
	returned by mode_for_size, rather than the mode of src itself,
	to choose between 32-bit and 64-bit patterns.
	(mips_mem_fits_mode_p): New function.
	* config/mips/mips.md (mov_<load>l, mov_<load>r): Use it to check
	that the size of the source matches the size of the destination.
	(mov_<store>l, mov_<store>r): Likewise.

gcc/testsuite/
	PR target/29006
	* gcc.c-torture/execute/pr29006.c: New test.

From-SVN: r116822