bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Generate slightly better unoptimized code for for-loops

Browse source 
The discriminant for Option values is either 0 or 1, so we can just
truncate the value to an i1, which ends up as a no-op for Options
containing pointers.
This commit is contained in:
Björn Steinbrink 2014-08-15 12:56:24 +02:00
parent 36db3866c0
commit 6c5d97a5da
1 changed files with 3 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

7
src/librustc/middle/trans/controlflow.rs
View file

@ -330,13 +330,12 @@ pub fn trans_for<'a>(
// Check the discriminant; if the `None` case, exit the loop.
let option_representation = adt::represent_type(loopback_bcx_out.ccx(),
method_result_type);
let i8_type = Type::i8(loopback_bcx_out.ccx());
let lldiscriminant = adt::trans_get_discr(loopback_bcx_out,
&*option_representation,
option_datum.val,
Some(i8_type));
let llzero = C_u8(loopback_bcx_out.ccx(), 0);
let llcondition = ICmp(loopback_bcx_out, IntNE, lldiscriminant, llzero);
None);
let i1_type = Type::i1(loopback_bcx_out.ccx());
let llcondition = Trunc(loopback_bcx_out, lldiscriminant, i1_type);
CondBr(loopback_bcx_out, llcondition, body_bcx_in.llbb, cleanup_llbb);
// Now we're in the body. Unpack the `Option` value into the programmer-