find more efficient way to bulk-init locally allocated data

[felix winkelmann]

For example, letrec creates code like this:

C_word t1517;
C_word t1518;
C_word t1519;
C_word ab[2291],*a=ab;
C_check_for_interrupt;
if(!C_stack_probe(&a)){
C_save_and_reclaim((void*)tr2,(void*)f_37706,2,t0,t1);}
t2=C_SCHEME_UNDEFINED;
t3=(*a=C_VECTOR_TYPE|1,a[1]=t2,tmp=(C_word)a,a+=2,tmp);
t4=C_SCHEME_UNDEFINED;
t5=(*a=C_VECTOR_TYPE|1,a[1]=t4,tmp=(C_word)a,a+=2,tmp);
t6=C_SCHEME_UNDEFINED;
t7=(*a=C_VECTOR_TYPE|1,a[1]=t6,tmp=(C_word)a,a+=2,tmp);
t8=C_SCHEME_UNDEFINED;
t9=(*a=C_VECTOR_TYPE|1,a[1]=t8,tmp=(C_word)a,a+=2,tmp);
t10=C_SCHEME_UNDEFINED;
t11=(*a=C_VECTOR_TYPE|1,a[1]=t10,tmp=(C_word)a,a+=2,tmp);
t12=C_SCHEME_UNDEFINED;
t13=(*a=C_VECTOR_TYPE|1,a[1]=t12,tmp=(C_word)a,a+=2,tmp);
t14=C_SCHEME_UNDEFINED;
t15=(*a=C_VECTOR_TYPE|1,a[1]=t14,tmp=(C_word)a,a+=2,tmp);
t16=C_SCHEME_UNDEFINED;
t17=(*a=C_VECTOR_TYPE|1,a[1]=t16,tmp=(C_word)a,a+=2,tmp);
t18=C_SCHEME_UNDEFINED;

One could use local array initializers or so to reduce the amount of code generated.

[felix winkelmann]

Since the compiler has to create the local data anyway, I can't see much improvement by using any other construct.