Pass the type of the store access, not the type of the store, into the

Pass the type of the store access, not the type of the store, into the
target hook.  This allows us to codegen a loop as:

LBB1_1: @cond_next
        mov r2, #0
        str r2, [r0, +r3, lsl #2]
        add r3, r3, #1
        cmn r3, #1
        bne LBB1_1      @cond_next

instead of:

LBB1_1: @cond_next
        mov r2, #0
        str r2, [r0], #+4
        add r3, r3, #1
        cmn r3, #1
        bne LBB1_1      @cond_next

This looks the same, but has one fewer induction variable (and therefore,
one fewer register) live in the loop.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35592 91177308-0d34-0410-b5e6-96231b3b80d8