mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

transmute: Avoid double copy for immediate values

Browse Source 
Currently, immediate values are copied into an alloca only to have an
addressable storage so that it can be used with memcpy. Obviously we
can skip the memcpy in this case.
This commit is contained in:
Björn Steinbrink 2013-07-11 18:44:40 +02:00
parent e95fcfafc7
commit 7e97277289
1 changed files with 11 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
src/librustc/middle/trans/foreign.rs
View File

@ -725,24 +725,21 @@ pub fn trans_intrinsic(ccx: @mut CrateContext,
}
if !ty::type_is_nil(out_type) {
// NB: Do not use a Load and Store here. This causes massive
// code bloat when `transmute` is used on large structural
// types.
let lldestptr = fcx.llretptr.get();
let lldestptr = PointerCast(bcx, lldestptr, Type::i8p());
let llsrcval = get_param(decl, first_real_arg);
let llsrcptr = if ty::type_is_immediate(ccx.tcx, in_type) {
let llsrcptr = alloca(bcx, llintype, "__llsrcptr");
Store(bcx, llsrcval, llsrcptr);
llsrcptr
if ty::type_is_immediate(ccx.tcx, in_type) {
let lldestptr = PointerCast(bcx, lldestptr, llintype.ptr_to());
Store(bcx, llsrcval, lldestptr);
} else {
llsrcval
};
let llsrcptr = PointerCast(bcx, llsrcptr, Type::i8p());
// NB: Do not use a Load and Store here. This causes massive
// code bloat when `transmute` is used on large structural
// types.
let lldestptr = PointerCast(bcx, lldestptr, Type::i8p());
let llsrcptr = PointerCast(bcx, llsrcval, Type::i8p());
let llsize = llsize_of(ccx, llintype);
call_memcpy(bcx, lldestptr, llsrcptr, llsize, 1);
let llsize = llsize_of(ccx, llintype);
call_memcpy(bcx, lldestptr, llsrcptr, llsize, 1);
};
}
}
"needs_drop" => {