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-rw-r--r--src/ir/subtype-exprs.h2
-rw-r--r--src/passes/CodeFolding.cpp7
-rw-r--r--src/passes/Flatten.cpp16
-rw-r--r--src/passes/Print.cpp11
-rw-r--r--src/wasm/wasm-validator.cpp23
-rw-r--r--src/wasm/wasm.cpp30
6 files changed, 48 insertions, 41 deletions
diff --git a/src/ir/subtype-exprs.h b/src/ir/subtype-exprs.h
index 1895c856a..e6ee1816d 100644
--- a/src/ir/subtype-exprs.h
+++ b/src/ir/subtype-exprs.h
@@ -122,7 +122,7 @@ struct SubtypingDiscoverer : public OverriddenVisitor<SubType> {
}
}
void visitIf(If* curr) {
- if (curr->ifFalse) {
+ if (curr->ifFalse && curr->type != Type::unreachable) {
self()->noteSubtype(curr->ifTrue, curr);
self()->noteSubtype(curr->ifFalse, curr);
}
diff --git a/src/passes/CodeFolding.cpp b/src/passes/CodeFolding.cpp
index 42331b747..305eb1278 100644
--- a/src/passes/CodeFolding.cpp
+++ b/src/passes/CodeFolding.cpp
@@ -234,6 +234,13 @@ struct CodeFolding
if (!curr->ifFalse) {
return;
}
+ if (curr->condition->type == Type::unreachable) {
+ // If the arms are foldable and concrete, we would be replacing an
+ // unreachable If with a concrete block, which may or may not be valid,
+ // depending on the context. Leave this for DCE rather than trying to
+ // handle that.
+ return;
+ }
// If both are blocks, look for a tail we can merge.
auto* left = curr->ifTrue->dynCast<Block>();
auto* right = curr->ifFalse->dynCast<Block>();
diff --git a/src/passes/Flatten.cpp b/src/passes/Flatten.cpp
index 37fa15b11..1c2cfbcd5 100644
--- a/src/passes/Flatten.cpp
+++ b/src/passes/Flatten.cpp
@@ -147,20 +147,24 @@ struct Flatten
// arm preludes go in the arms. we must also remove an if value
auto* originalIfTrue = iff->ifTrue;
auto* originalIfFalse = iff->ifFalse;
- auto type = iff->type;
+ auto type = iff->ifFalse ? Type::getLeastUpperBound(iff->ifTrue->type,
+ iff->ifFalse->type)
+ : Type::none;
Expression* prelude = nullptr;
if (type.isConcrete()) {
Index temp = builder.addVar(getFunction(), type);
if (iff->ifTrue->type.isConcrete()) {
iff->ifTrue = builder.makeLocalSet(temp, iff->ifTrue);
}
- if (iff->ifFalse && iff->ifFalse->type.isConcrete()) {
+ if (iff->ifFalse->type.isConcrete()) {
iff->ifFalse = builder.makeLocalSet(temp, iff->ifFalse);
}
- // the whole if (+any preludes from the condition) is now a prelude
- prelude = rep;
- // and we leave just a get of the value
- rep = builder.makeLocalGet(temp, type);
+ if (curr->type.isConcrete()) {
+ // the whole if (+any preludes from the condition) is now a prelude
+ prelude = rep;
+ // and we leave just a get of the value
+ rep = builder.makeLocalGet(temp, type);
+ }
}
iff->ifTrue = getPreludesWithExpression(originalIfTrue, iff->ifTrue);
if (iff->ifFalse) {
diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index bbf5f2a6b..4ca40f35a 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -460,9 +460,16 @@ struct PrintExpressionContents
}
void visitIf(If* curr) {
printMedium(o, "if");
- if (curr->type.isConcrete()) {
+ // Ifs are unreachable if their condition is unreachable, but in that case
+ // the arms might have some concrete type we have to account for to produce
+ // valid wat.
+ auto type = curr->type;
+ if (curr->condition->type == Type::unreachable && curr->ifFalse) {
+ type = Type::getLeastUpperBound(curr->ifTrue->type, curr->ifFalse->type);
+ }
+ if (type.isConcrete()) {
o << ' ';
- printBlockType(Signature(Type::none, curr->type));
+ printBlockType(Signature(Type::none, type));
}
}
void visitLoop(Loop* curr) {
diff --git a/src/wasm/wasm-validator.cpp b/src/wasm/wasm-validator.cpp
index 64c7fda02..e295d3931 100644
--- a/src/wasm/wasm-validator.cpp
+++ b/src/wasm/wasm-validator.cpp
@@ -865,7 +865,16 @@ void FunctionValidator::visitIf(If* curr) {
curr,
"returning if-else's false must have right type");
} else {
- if (curr->condition->type != Type::unreachable) {
+ if (curr->condition->type == Type::unreachable) {
+ shouldBeTrue(
+ curr->ifTrue->type == Type::unreachable ||
+ curr->ifFalse->type == Type::unreachable ||
+ (curr->ifTrue->type == Type::none &&
+ curr->ifFalse->type == Type::none) ||
+ Type::hasLeastUpperBound(curr->ifTrue->type, curr->ifFalse->type),
+ curr,
+ "arms of unreachable if-else must have compatible types");
+ } else {
shouldBeEqual(curr->ifTrue->type,
Type(Type::unreachable),
curr,
@@ -876,18 +885,6 @@ void FunctionValidator::visitIf(If* curr) {
"unreachable if-else must have unreachable false");
}
}
- if (curr->ifTrue->type.isConcrete()) {
- shouldBeSubType(curr->ifTrue->type,
- curr->type,
- curr,
- "if type must match concrete ifTrue");
- }
- if (curr->ifFalse->type.isConcrete()) {
- shouldBeSubType(curr->ifFalse->type,
- curr->type,
- curr,
- "if type must match concrete ifFalse");
- }
}
}
diff --git a/src/wasm/wasm.cpp b/src/wasm/wasm.cpp
index f89ef80c2..38f35411f 100644
--- a/src/wasm/wasm.cpp
+++ b/src/wasm/wasm.cpp
@@ -215,28 +215,20 @@ void Block::finalize(std::optional<Type> type_, Breakability breakability) {
}
void If::finalize(std::optional<Type> type_) {
- if (type_) {
- type = *type_;
- if (type == Type::none && (condition->type == Type::unreachable ||
- (ifFalse && ifTrue->type == Type::unreachable &&
- ifFalse->type == Type::unreachable))) {
- type = Type::unreachable;
- }
+ // The If is unreachable if the condition is unreachable or both arms are
+ // unreachable.
+ if (condition->type == Type::unreachable ||
+ (ifFalse && ifTrue->type == Type::unreachable &&
+ ifFalse->type == Type::unreachable)) {
+ type = Type::unreachable;
return;
}
- type = ifFalse ? Type::getLeastUpperBound(ifTrue->type, ifFalse->type)
- : Type::none;
- // if the arms return a value, leave it even if the condition
- // is unreachable, we still mark ourselves as having that type, e.g.
- // (if (result i32)
- // (unreachable)
- // (i32.const 10)
- // (i32.const 20)
- // )
- // otherwise, if the condition is unreachable, so is the if
- if (type == Type::none && condition->type == Type::unreachable) {
- type = Type::unreachable;
+ if (type_) {
+ type = *type_;
+ } else {
+ type = ifFalse ? Type::getLeastUpperBound(ifTrue->type, ifFalse->type)
+ : Type::none;
}
}
generated by cgit v1.2.3 (git 2.39.1) at 2025-04-06 22:10:59 +0000