librustc: Stop zeroing out allocas so much. Cuts 300K off librustc.

Author: pcwalton

src/librustc/middle/trans/base.rs

@@ -305,7 +305,7 @@ fn malloc_raw_dyn(bcx: block,
 
     // Allocate space:
     let tydesc = PointerCast(bcx, static_ti.tydesc, T_ptr(T_i8()));
-    let rval = alloca_zeroed(bcx, T_ptr(T_i8()));
+    let rval = alloca(bcx, T_ptr(T_i8()));
     let bcx = callee::trans_rtcall_or_lang_call(
         bcx,
         langcall,
@@ -1504,10 +1504,6 @@ fn alloca(cx: block, t: TypeRef) -> ValueRef {
     alloca_maybe_zeroed(cx, t, false)
 }
 
-fn alloca_zeroed(cx: block, t: TypeRef) -> ValueRef {
-    alloca_maybe_zeroed(cx, t, true)
-}
-
 fn alloca_maybe_zeroed(cx: block, t: TypeRef, zero: bool) -> ValueRef {
     let _icx = cx.insn_ctxt("alloca");
     if cx.unreachable {

src/librustc/middle/trans/closure.rs

@@ -525,7 +525,7 @@ fn make_opaque_cbox_take_glue(
 
         // Allocate memory, update original ptr, and copy existing data
         let opaque_tydesc = PointerCast(bcx, tydesc, T_ptr(T_i8()));
-        let rval = alloca_zeroed(bcx, T_ptr(T_i8()));
+        let rval = alloca(bcx, T_ptr(T_i8()));
         let bcx = callee::trans_rtcall_or_lang_call(
             bcx,
             bcx.tcx().lang_items.exchange_malloc_fn(),

src/librustc/middle/trans/glue.rs

@@ -134,7 +134,7 @@ pub fn free_ty_immediate(bcx: block, v: ValueRef, t: ty::t) -> block {
       ty::ty_evec(_, ty::vstore_box) |
       ty::ty_estr(ty::vstore_box) |
       ty::ty_opaque_closure_ptr(_) => {
-        let vp = alloca_zeroed(bcx, type_of(bcx.ccx(), t));
+        let vp = alloca(bcx, type_of(bcx.ccx(), t));
         Store(bcx, v, vp);
         free_ty(bcx, vp, t)
       }