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Remove unused function and associated tests (#1312)

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* Remove unused function and associated tests
* Removed unused imports
This commit is contained in:
C Burgos
2020-01-07 13:09:34 -05:00
committed by Andrew Brown
parent 46e58fbaaa
commit 8ff6d640d6
1 changed files with 0 additions and 117 deletions
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117
cranelift/codegen/src/dominator_tree.rs
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@@ -448,61 +448,6 @@ impl DominatorTree {
}
}
impl DominatorTree {
/// When splitting an `Ebb` using `Layout::split_ebb`, you can use this method to update
/// the dominator tree locally rather than recomputing it.
///
/// `old_ebb` is the `Ebb` before splitting, and `new_ebb` is the `Ebb` which now contains
/// the second half of `old_ebb`. `split_jump_inst` is the terminator jump instruction of
/// `old_ebb` that points to `new_ebb`.
pub fn recompute_split_ebb(&mut self, old_ebb: Ebb, new_ebb: Ebb, split_jump_inst: Inst) {
if !self.is_reachable(old_ebb) {
// old_ebb is unreachable, it stays so and new_ebb is unreachable too
self.nodes[new_ebb] = Default::default();
return;
}
// We use the RPO comparison on the postorder list so we invert the operands of the
// comparison
let old_ebb_postorder_index = self
.postorder
.as_slice()
.binary_search_by(|probe| self.rpo_cmp_ebb(old_ebb, *probe))
.expect("the old ebb is not declared to the dominator tree");
let new_ebb_rpo = self.insert_after_rpo(old_ebb, old_ebb_postorder_index, new_ebb);
self.nodes[new_ebb] = DomNode {
rpo_number: new_ebb_rpo,
idom: Some(split_jump_inst).into(),
};
}
// Insert new_ebb just after ebb in the RPO. This function checks
// if there is a gap in rpo numbers; if yes it returns the number in the gap and if
// not it renumbers.
fn insert_after_rpo(&mut self, ebb: Ebb, ebb_postorder_index: usize, new_ebb: Ebb) -> u32 {
let ebb_rpo_number = self.nodes[ebb].rpo_number;
let inserted_rpo_number = ebb_rpo_number + 1;
// If there is no gaps in RPo numbers to insert this new number, we iterate
// forward in RPO numbers and backwards in the postorder list of EBBs, renumbering the Ebbs
// until we find a gap
for (&current_ebb, current_rpo) in self.postorder[0..ebb_postorder_index]
.iter()
.rev()
.zip(inserted_rpo_number + 1..)
{
if self.nodes[current_ebb].rpo_number < current_rpo {
// There is no gap, we renumber
self.nodes[current_ebb].rpo_number = current_rpo;
} else {
// There is a gap, we stop the renumbering and exit
break;
}
}
// TODO: insert in constant time?
self.postorder.insert(ebb_postorder_index, new_ebb);
inserted_rpo_number
}
}
/// Optional pre-order information that can be computed for a dominator tree.
///
/// This data structure is computed from a `DominatorTree` and provides:
@@ -681,8 +626,6 @@ mod tests {
use crate::flowgraph::ControlFlowGraph;
use crate::ir::types::*;
use crate::ir::{Function, InstBuilder, TrapCode};
use crate::settings;
use crate::verifier::{verify_context, VerifierErrors};
#[test]
fn empty() {
@@ -886,64 +829,4 @@ mod tests {
assert!(!dt.dominates(jmp21, ebb2, &cur.func.layout));
assert!(dt.dominates(jmp21, jmp21, &cur.func.layout));
}
#[test]
fn renumbering() {
let mut func = Function::new();
let entry = func.dfg.make_ebb();
let ebb0 = func.dfg.make_ebb();
let ebb100 = func.dfg.make_ebb();
let mut cur = FuncCursor::new(&mut func);
cur.insert_ebb(entry);
cur.ins().jump(ebb0, &[]);
cur.insert_ebb(ebb0);
let cond = cur.ins().iconst(I32, 0);
let inst2 = cur.ins().brz(cond, ebb0, &[]);
let inst3 = cur.ins().brz(cond, ebb0, &[]);
let inst4 = cur.ins().brz(cond, ebb0, &[]);
let inst5 = cur.ins().brz(cond, ebb0, &[]);
cur.ins().jump(ebb100, &[]);
cur.insert_ebb(ebb100);
cur.ins().return_(&[]);
let mut cfg = ControlFlowGraph::with_function(cur.func);
let mut dt = DominatorTree::with_function(cur.func, &cfg);
let ebb1 = cur.func.dfg.make_ebb();
cur.func.layout.split_ebb(ebb1, inst2);
cur.goto_bottom(ebb0);
let middle_jump_inst = cur.ins().jump(ebb1, &[]);
dt.recompute_split_ebb(ebb0, ebb1, middle_jump_inst);
let ebb2 = cur.func.dfg.make_ebb();
cur.func.layout.split_ebb(ebb2, inst3);
cur.goto_bottom(ebb1);
let middle_jump_inst = cur.ins().jump(ebb2, &[]);
dt.recompute_split_ebb(ebb1, ebb2, middle_jump_inst);
let ebb3 = cur.func.dfg.make_ebb();
cur.func.layout.split_ebb(ebb3, inst4);
cur.goto_bottom(ebb2);
let middle_jump_inst = cur.ins().jump(ebb3, &[]);
dt.recompute_split_ebb(ebb2, ebb3, middle_jump_inst);
let ebb4 = cur.func.dfg.make_ebb();
cur.func.layout.split_ebb(ebb4, inst5);
cur.goto_bottom(ebb3);
let middle_jump_inst = cur.ins().jump(ebb4, &[]);
dt.recompute_split_ebb(ebb3, ebb4, middle_jump_inst);
cfg.compute(cur.func);
let flags = settings::Flags::new(settings::builder());
let mut errors = VerifierErrors::default();
verify_context(cur.func, &cfg, &dt, &flags, &mut errors).unwrap();
assert!(errors.0.is_empty());
}
}