Compiled with optimization level 2:

  gcc -S -O2 if1.c

max:                            
        pushl   %ebp            
        movl    %esp, %ebp      
        movl    8(%ebp), %edx     reg2 = x
        movl    12(%ebp), %eax    reg1 = y
        cmpl    %edx, %eax        [cmp reg2, reg1]
        jge     .L2               if (reg1 >= reg2) goto L2
        movl    %edx, %eax        reg1 = reg2
.L2:                            L2:
        popl    %ebp              
        ret                       return