Rollup merge of #21941 - dotdash:with_cond_false, r=Aatch

Currently \"k / 2\" generates one (k: uint) or two (k: int) \"br false,
...\" instructions and the corresponding basic blocks, producing quite
some noise and making the code unnecessarily hard to read.

Additionally we can skip translation if the code would end up
unreachable anyway.
This commit is contained in:
Manish Goregaokar 2015-02-06 05:37:49 +05:30
commit cfae247ce0
2 changed files with 10 additions and 2 deletions

View File

@ -889,11 +889,13 @@ fn compile_guard<'a, 'p, 'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
}
}
for (_, &binding_info) in &data.bindings_map {
bcx.fcx.lllocals.borrow_mut().remove(&binding_info.id);
}
with_cond(bcx, Not(bcx, val, guard_expr.debug_loc()), |bcx| {
// Guard does not match: remove all bindings from the lllocals table
for (_, &binding_info) in &data.bindings_map {
call_lifetime_end(bcx, binding_info.llmatch);
bcx.fcx.lllocals.borrow_mut().remove(&binding_info.id);
}
match chk {
// If the default arm is the only one left, move on to the next

View File

@ -1081,6 +1081,12 @@ pub fn with_cond<'blk, 'tcx, F>(bcx: Block<'blk, 'tcx>,
F: FnOnce(Block<'blk, 'tcx>) -> Block<'blk, 'tcx>,
{
let _icx = push_ctxt("with_cond");
if bcx.unreachable.get() ||
(common::is_const(val) && common::const_to_uint(val) == 0) {
return bcx;
}
let fcx = bcx.fcx;
let next_cx = fcx.new_temp_block("next");
let cond_cx = fcx.new_temp_block("cond");