Remove ValueData::Alias

fe-lang · Jun 30, 2024 · 45a065f · 45a065f
1 parent 660d0b8
commit 45a065f
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Showing 6 changed files with 14 additions and 36 deletions.
diff --git a/crates/codegen/src/optim/gvn.rs b/crates/codegen/src/optim/gvn.rs
@@ -504,7 +504,7 @@ impl GvnSolver {
         value: Value,
         edge: Edge,
     ) -> Value {
-        let mut rep_value = self.leader(func.dfg.resolve_alias(value));
+        let mut rep_value = self.leader(value);
 
         if let Some(inferred_value) = self.infer_value_impl(edge, rep_value) {
             rep_value = inferred_value;

diff --git a/crates/codegen/src/optim/sccp.rs b/crates/codegen/src/optim/sccp.rs
@@ -140,8 +140,6 @@ impl SccpSolver {
         for (i, from) in func.dfg.phi_blocks(insn).iter().enumerate() {
             if self.is_reachable(func, *from, block) {
                 let phi_arg = func.dfg.insn_arg(insn, i);
-                let phi_arg = func.dfg.resolve_alias(phi_arg);
-
                 let v_cell = self.lattice[phi_arg];
                 eval_result = eval_result.join(v_cell);
             }

diff --git a/crates/codegen/src/optim/simplify_impl.rs b/crates/codegen/src/optim/simplify_impl.rs
@@ -17,7 +17,7 @@ use generated_code::{Context, SimplifyRawResult};
 
 pub fn simplify_insn(dfg: &mut DataFlowGraph, insn: Insn) -> Option<SimplifyResult> {
     if dfg.is_phi(insn) {
-        return simplify_phi(dfg, dfg.insn_data(insn));
+        return simplify_phi(dfg.insn_data(insn));
     }
 
     let mut ctx = SimplifyContext::new(dfg);
@@ -27,7 +27,7 @@ pub fn simplify_insn(dfg: &mut DataFlowGraph, insn: Insn) -> Option<SimplifyResu
 
 pub fn simplify_insn_data(dfg: &mut DataFlowGraph, data: InsnData) -> Option<SimplifyResult> {
     if matches!(data, InsnData::Phi { .. }) {
-        return simplify_phi(dfg, &data);
+        return simplify_phi(&data);
     }
 
     let mut ctx = SimplifyContext::new(dfg);
@@ -40,12 +40,12 @@ pub enum SimplifyResult {
     Insn(InsnData),
 }
 
-fn simplify_phi(dfg: &DataFlowGraph, insn_data: &InsnData) -> Option<SimplifyResult> {
+fn simplify_phi(insn_data: &InsnData) -> Option<SimplifyResult> {
     match insn_data {
         InsnData::Phi { values, .. } => {
             let mut values = values.iter().copied();
             let first_value = values.next().unwrap();
-            if values.all(|value| dfg.is_same_value(first_value, value)) {
+            if values.all(|value| value == first_value) {
                 Some(SimplifyResult::Value(first_value))
             } else {
                 None
@@ -499,7 +499,7 @@ impl<'a> generated_code::Context for SimplifyContext<'a> {
 
     fn is_eq(&mut self, arg0: ExprValue, arg1: ExprValue) -> Option<()> {
         match (arg0.as_value(), arg1.as_value()) {
-            (Some(val1), Some(val2)) => self.dfg.is_same_value(val1, val2),
+            (Some(val1), Some(val2)) => val1 == val2,
             _ => arg0 == arg1,
         }
         .then_some(())

diff --git a/crates/ir/src/dfg.rs b/crates/ir/src/dfg.rs
@@ -82,23 +82,15 @@ impl DataFlowGraph {
     }
 
     pub fn change_to_alias(&mut self, value: Value, alias: Value) {
-        self.values[value] = ValueData::Alias {
-            alias: self.resolve_alias(alias),
-        }
-    }
-
-    pub fn resolve_alias(&self, mut value: Value) -> Value {
-        for _ in 0..self.values.len() {
-            match self.values[value] {
-                ValueData::Insn { .. }
-                | ValueData::Arg { .. }
-                | ValueData::Immediate { .. }
-                | ValueData::Global { .. } => return value,
-                ValueData::Alias { alias } => value = alias,
+        let mut users = std::mem::take(&mut self.users[value]);
+        for insn in &users {
+            for arg in self.insns[*insn].args_mut() {
+                if *arg == value {
+                    *arg = alias;
+                }
             }
         }
-
-        panic!("alias loop detected");
+        self.users[alias].append(&mut users);
     }
 
     pub fn make_result(&mut self, insn: Insn) -> Option<ValueData> {
@@ -159,21 +151,18 @@ impl DataFlowGraph {
     }
 
     pub fn value_insn(&self, value: Value) -> Option<Insn> {
-        let value = self.resolve_alias(value);
         match self.value_data(value) {
             ValueData::Insn { insn, .. } => Some(*insn),
             _ => None,
         }
     }
 
     pub fn value_ty(&self, value: Value) -> Type {
-        let value = self.resolve_alias(value);
         match &self.values[value] {
             ValueData::Insn { ty, .. }
             | ValueData::Arg { ty, .. }
             | ValueData::Immediate { ty, .. }
             | ValueData::Global { ty, .. } => *ty,
-            ValueData::Alias { .. } => unreachable!(),
         }
     }
 
@@ -182,7 +171,6 @@ impl DataFlowGraph {
     }
 
     pub fn value_imm(&self, value: Value) -> Option<Immediate> {
-        let value = self.resolve_alias(value);
         match self.value_data(value) {
             ValueData::Immediate { imm, .. } => Some(*imm),
             ValueData::Global { gv, .. } => self.ctx.with_gv_store(|s| {
@@ -199,7 +187,6 @@ impl DataFlowGraph {
     }
 
     pub fn value_gv(&self, value: Value) -> Option<GlobalVariable> {
-        let value = self.resolve_alias(value);
         match self.value_data(value) {
             ValueData::Global { gv, .. } => Some(*gv),
             _ => None,
@@ -281,18 +268,13 @@ impl DataFlowGraph {
         self.insns[insn].is_branch()
     }
 
-    pub fn is_same_value(&self, v0: Value, v1: Value) -> bool {
-        self.resolve_alias(v0) == self.resolve_alias(v1)
-    }
-
     /// Returns `true` if `value` is an immediate.
     pub fn is_imm(&self, value: Value) -> bool {
         self.value_imm(value).is_some()
     }
 
     /// Returns `true` if `value` is a function argument.
     pub fn is_arg(&self, value: Value) -> bool {
-        let value = self.resolve_alias(value);
         matches!(self.value_data(value), ValueData::Arg { .. })
     }
 }

diff --git a/crates/ir/src/ir_writer.rs b/crates/ir/src/ir_writer.rs
@@ -205,7 +205,7 @@ trait IrWrite {
 
 impl IrWrite for Value {
     fn write(&self, writer: &mut FuncWriter, w: &mut impl io::Write) -> io::Result<()> {
-        let value = writer.func.dfg.resolve_alias(*self);
+        let value = *self;
         if let Some(imm) = writer.func.dfg.value_imm(value) {
             write!(w, "{}.", imm)?;
             let ty = writer.func.dfg.value_ty(value);

diff --git a/crates/ir/src/value.rs b/crates/ir/src/value.rs
@@ -80,8 +80,6 @@ pub enum ValueData {
 
     /// The value is a function argument.
     Arg { ty: Type, idx: usize },
-    /// The value is alias to another value.
-    Alias { alias: Value },
 
     /// The value is immediate value.
     Immediate { imm: Immediate, ty: Type },