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cranelift: Remove brz and brnz (#5630)

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Remove the brz and brnz instructions, as their behavior is now redundant with brif.
This commit is contained in:
Trevor Elliott
2023-01-30 12:34:56 -08:00
committed by GitHub
parent 77cf547f41
commit a5698cedf8
247 changed files with 2947 additions and 3754 deletions
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72
cranelift/codegen/src/flowgraph.rs
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@@ -11,17 +11,14 @@
//!
//! ...
//!
//! brz vx, Block1 ; end of basic block
//! brif vx, Block1, Block2 ; end of basic block
//!
//! ... ; beginning of basic block
//!
//! ...
//!
//! jmp Block2 ; end of basic block
//! Block1:
//! jump block3
//! ```
//!
//! Here `Block1` and `Block2` would each have a single predecessor denoted as `(Block0, brz)`
//! and `(Block0, jmp Block2)` respectively.
//! Here `Block1` and `Block2` would each have a single predecessor denoted as `(Block0, brif)`,
//! while `Block3` would have a single predecessor denoted as `(Block1, jump block3)`.
use crate::bforest;
use crate::entity::SecondaryMap;
@@ -120,7 +117,7 @@ impl ControlFlowGraph {
}
fn compute_block(&mut self, func: &Function, block: Block) {
for inst in func.layout.block_likely_branches(block) {
if let Some(inst) = func.layout.last_inst(block) {
match func.dfg.analyze_branch(inst) {
BranchInfo::SingleDest(dest) => {
self.add_edge(block, inst, dest.block(&func.dfg.value_lists));
@@ -253,21 +250,17 @@ mod tests {
let block1 = func.dfg.make_block();
let block2 = func.dfg.make_block();
let br_block0_block2;
let br_block1_block1;
let jmp_block0_block1;
let jmp_block1_block2;
let br_block0_block2_block1;
let br_block1_block1_block2;
{
let mut cur = FuncCursor::new(&mut func);
cur.insert_block(block0);
br_block0_block2 = cur.ins().brnz(cond, block2, &[]);
jmp_block0_block1 = cur.ins().jump(block1, &[]);
br_block0_block2_block1 = cur.ins().brif(cond, block2, &[], block1, &[]);
cur.insert_block(block1);
br_block1_block1 = cur.ins().brnz(cond, block1, &[]);
jmp_block1_block2 = cur.ins().jump(block2, &[]);
br_block1_block1_block2 = cur.ins().brif(cond, block1, &[], block2, &[]);
cur.insert_block(block2);
}
@@ -288,19 +281,23 @@ mod tests {
assert_eq!(block2_predecessors.len(), 2);
assert_eq!(
block1_predecessors.contains(&BlockPredecessor::new(block0, jmp_block0_block1)),
block1_predecessors
.contains(&BlockPredecessor::new(block0, br_block0_block2_block1)),
true
);
assert_eq!(
block1_predecessors.contains(&BlockPredecessor::new(block1, br_block1_block1)),
block1_predecessors
.contains(&BlockPredecessor::new(block1, br_block1_block1_block2)),
true
);
assert_eq!(
block2_predecessors.contains(&BlockPredecessor::new(block0, br_block0_block2)),
block2_predecessors
.contains(&BlockPredecessor::new(block0, br_block0_block2_block1)),
true
);
assert_eq!(
block2_predecessors.contains(&BlockPredecessor::new(block1, jmp_block1_block2)),
block2_predecessors
.contains(&BlockPredecessor::new(block1, br_block1_block1_block2)),
true
);
@@ -309,11 +306,22 @@ mod tests {
assert_eq!(block2_successors, []);
}
// Change some instructions and recompute block0
func.dfg.replace(br_block0_block2).brnz(cond, block1, &[]);
func.dfg.replace(jmp_block0_block1).return_(&[]);
// Add a new block to hold a return instruction
let ret_block = func.dfg.make_block();
{
let mut cur = FuncCursor::new(&mut func);
cur.insert_block(ret_block);
cur.ins().return_(&[]);
}
// Change some instructions and recompute block0 and ret_block
func.dfg
.replace(br_block0_block2_block1)
.brif(cond, block1, &[], ret_block, &[]);
cfg.recompute_block(&mut func, block0);
let br_block0_block1 = br_block0_block2;
cfg.recompute_block(&mut func, ret_block);
let br_block0_block1_ret_block = br_block0_block2_block1;
{
let block0_predecessors = cfg.pred_iter(block0).collect::<Vec<_>>();
@@ -329,23 +337,27 @@ mod tests {
assert_eq!(block2_predecessors.len(), 1);
assert_eq!(
block1_predecessors.contains(&BlockPredecessor::new(block0, br_block0_block1)),
block1_predecessors
.contains(&BlockPredecessor::new(block0, br_block0_block1_ret_block)),
true
);
assert_eq!(
block1_predecessors.contains(&BlockPredecessor::new(block1, br_block1_block1)),
block1_predecessors
.contains(&BlockPredecessor::new(block1, br_block1_block1_block2)),
true
);
assert_eq!(
block2_predecessors.contains(&BlockPredecessor::new(block0, br_block0_block2)),
block2_predecessors
.contains(&BlockPredecessor::new(block0, br_block0_block1_ret_block)),
false
);
assert_eq!(
block2_predecessors.contains(&BlockPredecessor::new(block1, jmp_block1_block2)),
block2_predecessors
.contains(&BlockPredecessor::new(block1, br_block1_block1_block2)),
true
);
assert_eq!(block0_successors.collect::<Vec<_>>(), [block1]);
assert_eq!(block0_successors.collect::<Vec<_>>(), [block1, ret_block]);
assert_eq!(block1_successors.collect::<Vec<_>>(), [block1, block2]);
assert_eq!(block2_successors.collect::<Vec<_>>(), []);
}