From 34ec4b4e44b9fdc22c28d7485a6b5e6e3cb93556 Mon Sep 17 00:00:00 2001
From: Trevor Elliott <telliott@fastly.com>
Date: Wed, 8 Feb 2023 15:42:24 -0800
Subject: [PATCH] Reuse `inst_predicates::visit_block_succs` in more places
 (#5750)

Following up from #5730, replace some explicit matching over branch instructions with a use of inst_predicates::visit_block_succs.
---
 cranelift/codegen/src/dominator_tree.rs | 29 +++------------------
 cranelift/codegen/src/flowgraph.rs      | 34 ++++---------------------
 2 files changed, 8 insertions(+), 55 deletions(-)

diff --git a/cranelift/codegen/src/dominator_tree.rs b/cranelift/codegen/src/dominator_tree.rs
index 06594aaa98..23ccb1783a 100644
--- a/cranelift/codegen/src/dominator_tree.rs
+++ b/cranelift/codegen/src/dominator_tree.rs
@@ -2,7 +2,8 @@
 
 use crate::entity::SecondaryMap;
 use crate::flowgraph::{BlockPredecessor, ControlFlowGraph};
-use crate::ir::{self, Block, ExpandedProgramPoint, Function, Inst, Layout, ProgramOrder, Value};
+use crate::inst_predicates;
+use crate::ir::{Block, ExpandedProgramPoint, Function, Inst, Layout, ProgramOrder, Value};
 use crate::packed_option::PackedOption;
 use crate::timing;
 use alloc::vec::Vec;
@@ -350,31 +351,7 @@ impl DominatorTree {
     /// post-order. Split-invariant means that if a block is split in two, we get the same
     /// post-order except for the insertion of the new block header at the split point.
     fn push_successors(&mut self, func: &Function, block: Block) {
-        if let Some(inst) = func.layout.last_inst(block) {
-            match &func.dfg.insts[inst] {
-                ir::InstructionData::Jump {
-                    destination: succ, ..
-                } => self.push_if_unseen(succ.block(&func.dfg.value_lists)),
-                ir::InstructionData::Brif {
-                    blocks: [block_then, block_else],
-                    ..
-                } => {
-                    self.push_if_unseen(block_then.block(&func.dfg.value_lists));
-                    self.push_if_unseen(block_else.block(&func.dfg.value_lists));
-                }
-                ir::InstructionData::BranchTable {
-                    table: jt,
-                    destination: dest,
-                    ..
-                } => {
-                    for succ in func.stencil.dfg.jump_tables[*jt].iter() {
-                        self.push_if_unseen(*succ);
-                    }
-                    self.push_if_unseen(*dest);
-                }
-                inst => debug_assert!(!inst.opcode().is_branch()),
-            }
-        }
+        inst_predicates::visit_block_succs(func, block, |_, succ, _| self.push_if_unseen(succ))
     }
 
     /// Push `block` onto `self.stack` if it has not already been seen.
diff --git a/cranelift/codegen/src/flowgraph.rs b/cranelift/codegen/src/flowgraph.rs
index 8419228006..fa62d3caeb 100644
--- a/cranelift/codegen/src/flowgraph.rs
+++ b/cranelift/codegen/src/flowgraph.rs
@@ -22,7 +22,8 @@
 
 use crate::bforest;
 use crate::entity::SecondaryMap;
-use crate::ir::{self, Block, Function, Inst};
+use crate::inst_predicates;
+use crate::ir::{Block, Function, Inst};
 use crate::timing;
 use core::mem;
 
@@ -116,34 +117,9 @@ impl ControlFlowGraph {
     }
 
     fn compute_block(&mut self, func: &Function, block: Block) {
-        if let Some(inst) = func.layout.last_inst(block) {
-            match &func.dfg.insts[inst] {
-                ir::InstructionData::Jump {
-                    destination: dest, ..
-                } => {
-                    self.add_edge(block, inst, dest.block(&func.dfg.value_lists));
-                }
-                ir::InstructionData::Brif {
-                    blocks: [block_then, block_else],
-                    ..
-                } => {
-                    self.add_edge(block, inst, block_then.block(&func.dfg.value_lists));
-                    self.add_edge(block, inst, block_else.block(&func.dfg.value_lists));
-                }
-                ir::InstructionData::BranchTable {
-                    table: jt,
-                    destination: dest,
-                    ..
-                } => {
-                    self.add_edge(block, inst, *dest);
-
-                    for dest in func.stencil.dfg.jump_tables[*jt].iter() {
-                        self.add_edge(block, inst, *dest);
-                    }
-                }
-                inst => debug_assert!(!inst.opcode().is_branch()),
-            }
-        }
+        inst_predicates::visit_block_succs(func, block, |inst, dest, _| {
+            self.add_edge(block, inst, dest);
+        });
     }
 
     fn invalidate_block_successors(&mut self, block: Block) {