Emit comparisons against the sign bit better. Codegen this:

Emit comparisons against the sign bit better.  Codegen this:

bool %test1(long %X) {
        %A = setlt long %X, 0
        ret bool %A
}

like this:

test1:
        cmpl $0, 8(%esp)
        setl %al
        movzbl %al, %eax
        ret

instead of:

test1:
        movl 8(%esp), %ecx
        cmpl $0, %ecx
        setl %al
        movzbw %al, %ax
        cmpl $0, 4(%esp)
        setb %dl
        movzbw %dl, %dx
        cmpl $0, %ecx
        cmove %dx, %ax
        movzbl %al, %eax
        ret

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21243 91177308-0d34-0410-b5e6-96231b3b80d8