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-rw-r--r--src/ir/effects.h14
-rw-r--r--src/passes/OptimizeInstructions.cpp49
-rw-r--r--test/lit/passes/optimize-instructions-gc.wast30
-rw-r--r--test/lit/passes/optimize-instructions.wast161
4 files changed, 210 insertions, 44 deletions
diff --git a/src/ir/effects.h b/src/ir/effects.h
index 3d71a8433..f9b6ca6fc 100644
--- a/src/ir/effects.h
+++ b/src/ir/effects.h
@@ -716,6 +716,20 @@ private:
}
};
+// Calculate effects only on the node itself (shallowly), and not on
+// children.
+class ShallowEffectAnalyzer : public EffectAnalyzer {
+public:
+ ShallowEffectAnalyzer(const PassOptions& passOptions,
+ FeatureSet features,
+ Expression* ast = nullptr)
+ : EffectAnalyzer(passOptions, features) {
+ if (ast) {
+ visit(ast);
+ }
+ }
+};
+
} // namespace wasm
#endif // wasm_ir_effects_h
diff --git a/src/passes/OptimizeInstructions.cpp b/src/passes/OptimizeInstructions.cpp
index 5df057dcc..5eba1e3b9 100644
--- a/src/passes/OptimizeInstructions.cpp
+++ b/src/passes/OptimizeInstructions.cpp
@@ -2786,10 +2786,6 @@ private:
// Optimize an if-else or a select, something with a condition and two
// arms with outputs.
template<typename T> void optimizeTernary(T* curr) {
- if (curr->type == Type::unreachable) {
- return;
- }
-
using namespace Match;
Builder builder(*getModule());
@@ -2809,7 +2805,7 @@ private:
// (Y)
// )
// )
- {
+ if (curr->type != Type::unreachable) {
Unary* un;
Expression* x;
Const* c;
@@ -2860,27 +2856,42 @@ private:
// as we go, then do a single replaceCurrent() at the end.
SmallVector<Expression*, 1> chain;
while (1) {
- // TODO: handle none as well as concrete types (can pull a drop out, for
- // example)
- // TODO: consider the case with more children than 1
- if (curr->ifTrue->type.isConcrete() &&
- !Properties::isControlFlowStructure(curr->ifTrue) &&
+ // Ignore control flow structures (which are handled in MergeBlocks).
+ if (!Properties::isControlFlowStructure(curr->ifTrue) &&
ExpressionAnalyzer::shallowEqual(curr->ifTrue, curr->ifFalse)) {
+ // TODO: consider the case with more than one child.
ChildIterator ifTrueChildren(curr->ifTrue);
if (ifTrueChildren.children.size() == 1) {
+ ChildIterator ifFalseChildren(curr->ifFalse);
+ // ifTrue and ifFalse's children will become the direct children of
+ // curr, and so there must be an LUB for curr to have a proper type.
+ // An example where that does not happen is this:
+ //
+ // (if
+ // (condition)
+ // (drop (i32.const 1))
+ // (drop (f64.const 2.0))
+ // )
+ auto* ifTrueChild = *ifTrueChildren.begin();
+ auto* ifFalseChild = *ifFalseChildren.begin();
+ bool validTypes =
+ Type::hasLeastUpperBound(ifTrueChild->type, ifFalseChild->type);
// If the expression we are about to move outside has side effects,
- // we cannot replace two instances with one (and there might be
- // ordering issues as well, for a select's condition).
- // TODO: handle certain side effects when possible
- EffectAnalyzer shallowEffects(getPassOptions(),
- getModule()->features);
- shallowEffects.visit(curr->ifTrue);
- if (!shallowEffects.hasSideEffects()) {
+ // then we cannot do so in general with a select: we'd be reducing
+ // the amount of the effects as well as moving them. For an if,
+ // the side effects execute once, so there is no problem.
+ // TODO: handle certain side effects when possible in select
+ bool validEffects = std::is_same<T, If>::value ||
+ !ShallowEffectAnalyzer(getPassOptions(),
+ getModule()->features,
+ curr->ifTrue)
+ .hasSideEffects();
+ if (validTypes && validEffects) {
// Replace ifTrue with its child.
- curr->ifTrue = *ifTrueChildren.begin();
+ curr->ifTrue = ifTrueChild;
// Relace ifFalse with its child, and reuse that node outside.
auto* reuse = curr->ifFalse;
- curr->ifFalse = *ChildIterator(curr->ifFalse).begin();
+ curr->ifFalse = ifFalseChild;
// curr's type may have changed, if the instructions we moved out
// had different input types than output types.
curr->finalize();
diff --git a/test/lit/passes/optimize-instructions-gc.wast b/test/lit/passes/optimize-instructions-gc.wast
index 3ae0e1d91..c0474a823 100644
--- a/test/lit/passes/optimize-instructions-gc.wast
+++ b/test/lit/passes/optimize-instructions-gc.wast
@@ -849,7 +849,7 @@
)
)
)
- ;; CHECK: (func $ternary-identical-arms-but-side-effect (param $x (ref null $struct)) (param $y (ref null $struct)) (param $z i32)
+ ;; CHECK: (func $select-identical-arms-but-side-effect (param $x (ref null $struct)) (param $y (ref null $struct)) (param $z i32)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (select
;; CHECK-NEXT: (struct.get_u $struct $i8
@@ -862,7 +862,7 @@
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: )
- (func $ternary-identical-arms-but-side-effect (param $x (ref null $struct)) (param $y (ref null $struct)) (param $z i32)
+ (func $select-identical-arms-but-side-effect (param $x (ref null $struct)) (param $y (ref null $struct)) (param $z i32)
(drop
(select
;; the arms are equal but have side effects
@@ -901,4 +901,30 @@
)
)
)
+ ;; CHECK: (func $if-identical-arms-with-side-effect (param $x (ref null $struct)) (param $y (ref null $struct)) (param $z i32)
+ ;; CHECK-NEXT: (drop
+ ;; CHECK-NEXT: (struct.get_u $struct $i8
+ ;; CHECK-NEXT: (if (result (ref null $struct))
+ ;; CHECK-NEXT: (local.get $z)
+ ;; CHECK-NEXT: (local.get $x)
+ ;; CHECK-NEXT: (local.get $y)
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ (func $if-identical-arms-with-side-effect (param $x (ref null $struct)) (param $y (ref null $struct)) (param $z i32)
+ (drop
+ (if (result i32)
+ (local.get $z)
+ ;; the arms are equal and have side effects, but that is ok with an if
+ ;; which only executes one side anyhow
+ (struct.get_u $struct 0
+ (local.get $x)
+ )
+ (struct.get_u $struct 0
+ (local.get $y)
+ )
+ )
+ )
+ )
)
diff --git a/test/lit/passes/optimize-instructions.wast b/test/lit/passes/optimize-instructions.wast
index 7150fc839..3ed0b3115 100644
--- a/test/lit/passes/optimize-instructions.wast
+++ b/test/lit/passes/optimize-instructions.wast
@@ -101,12 +101,10 @@
)
)
;; CHECK: (func $if-eqz-two-arms (param $i1 i32)
- ;; CHECK-NEXT: (if
- ;; CHECK-NEXT: (local.get $i1)
- ;; CHECK-NEXT: (drop
+ ;; CHECK-NEXT: (drop
+ ;; CHECK-NEXT: (if (result i32)
+ ;; CHECK-NEXT: (local.get $i1)
;; CHECK-NEXT: (i32.const 12)
- ;; CHECK-NEXT: )
- ;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 11)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
@@ -125,14 +123,12 @@
)
)
;; CHECK: (func $if-eqz-two-arms-i64 (param $i2 i64)
- ;; CHECK-NEXT: (if
- ;; CHECK-NEXT: (i64.eqz
- ;; CHECK-NEXT: (local.get $i2)
- ;; CHECK-NEXT: )
- ;; CHECK-NEXT: (drop
+ ;; CHECK-NEXT: (drop
+ ;; CHECK-NEXT: (if (result i32)
+ ;; CHECK-NEXT: (i64.eqz
+ ;; CHECK-NEXT: (local.get $i2)
+ ;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 11)
- ;; CHECK-NEXT: )
- ;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 12)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
@@ -11928,29 +11924,44 @@
)
)
)
- ;; CHECK: (func $ternary-identical-arms-but-type-is-none (param $x i32) (param $y i32) (param $z i32)
- ;; CHECK-NEXT: (if
- ;; CHECK-NEXT: (local.get $z)
- ;; CHECK-NEXT: (drop
- ;; CHECK-NEXT: (i32.eqz
+ ;; CHECK: (func $ternary-identical-arms-and-type-is-none (param $x i32) (param $y i32) (param $z i32)
+ ;; CHECK-NEXT: (drop
+ ;; CHECK-NEXT: (i32.eqz
+ ;; CHECK-NEXT: (if (result i32)
+ ;; CHECK-NEXT: (local.get $z)
;; CHECK-NEXT: (local.get $x)
- ;; CHECK-NEXT: )
- ;; CHECK-NEXT: )
- ;; CHECK-NEXT: (drop
- ;; CHECK-NEXT: (i32.eqz
;; CHECK-NEXT: (local.get $y)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: )
- (func $ternary-identical-arms-but-type-is-none (param $x i32) (param $y i32) (param $z i32)
+ (func $ternary-identical-arms-and-type-is-none (param $x i32) (param $y i32) (param $z i32)
(if
(local.get $z)
- ;; identical arms, but type is none
(drop (i32.eqz (local.get $x)))
(drop (i32.eqz (local.get $y)))
)
)
+ ;; CHECK: (func $ternary-identical-arms-and-type-is-none-child-types-mismatch (param $x i32) (param $y i32) (param $z i32)
+ ;; CHECK-NEXT: (if
+ ;; CHECK-NEXT: (local.get $z)
+ ;; CHECK-NEXT: (drop
+ ;; CHECK-NEXT: (i32.const 1)
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: (drop
+ ;; CHECK-NEXT: (f64.const 2.34)
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ (func $ternary-identical-arms-and-type-is-none-child-types-mismatch (param $x i32) (param $y i32) (param $z i32)
+ (if
+ (local.get $z)
+ ;; the drop cannot be hoisted out, since the children's type mismatch
+ ;; would not allow us to give a proper type to the if.
+ (drop (i32.const 1))
+ (drop (f64.const 2.34))
+ )
+ )
;; CHECK: (func $ternary-identical-arms-but-block (param $x i32) (param $y i32) (param $z i32)
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (select
@@ -12013,4 +12024,108 @@
)
)
)
+ ;; CHECK: (func $ternary-identical-arms-br_if-same (param $x i32) (param $y i32) (param $z i32)
+ ;; CHECK-NEXT: (block $block
+ ;; CHECK-NEXT: (br_if $block
+ ;; CHECK-NEXT: (if (result i32)
+ ;; CHECK-NEXT: (local.get $z)
+ ;; CHECK-NEXT: (local.get $x)
+ ;; CHECK-NEXT: (local.get $y)
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ (func $ternary-identical-arms-br_if-same (param $x i32) (param $y i32) (param $z i32)
+ (block $block
+ (if
+ (local.get $z)
+ ;; two br_ifs with the same target are shallowly identical
+ (br_if $block
+ (local.get $x)
+ )
+ (br_if $block
+ (local.get $y)
+ )
+ )
+ )
+ )
+ ;; CHECK: (func $ternary-identical-arms-br_if-different (param $x i32) (param $y i32) (param $z i32)
+ ;; CHECK-NEXT: (block $block1
+ ;; CHECK-NEXT: (block $block2
+ ;; CHECK-NEXT: (if
+ ;; CHECK-NEXT: (local.get $z)
+ ;; CHECK-NEXT: (br_if $block1
+ ;; CHECK-NEXT: (local.get $x)
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: (br_if $block2
+ ;; CHECK-NEXT: (local.get $y)
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ (func $ternary-identical-arms-br_if-different (param $x i32) (param $y i32) (param $z i32)
+ (block $block1
+ (block $block2
+ (if
+ (local.get $z)
+ ;; two br_ifs with different targets are not shallowly identical
+ (br_if $block1
+ (local.get $x)
+ )
+ (br_if $block2
+ (local.get $y)
+ )
+ )
+ )
+ )
+ )
+ ;; CHECK: (func $ternary-identical-arms-return (param $x i32) (param $y i32) (param $z i32) (result i32)
+ ;; CHECK-NEXT: (block $block
+ ;; CHECK-NEXT: (return
+ ;; CHECK-NEXT: (if (result i32)
+ ;; CHECK-NEXT: (local.get $z)
+ ;; CHECK-NEXT: (local.get $x)
+ ;; CHECK-NEXT: (local.get $y)
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ (func $ternary-identical-arms-return (param $x i32) (param $y i32) (param $z i32) (result i32)
+ (block $block
+ (if
+ (local.get $z)
+ (return
+ (local.get $x)
+ )
+ (return
+ (local.get $y)
+ )
+ )
+ )
+ )
+ ;; CHECK: (func $send-i32 (param $0 i32)
+ ;; CHECK-NEXT: (nop)
+ ;; CHECK-NEXT: )
+ (func $send-i32 (param i32))
+ ;; CHECK: (func $ternary-identical-arms-call (param $x i32) (param $y i32) (param $z i32)
+ ;; CHECK-NEXT: (call $send-i32
+ ;; CHECK-NEXT: (if (result i32)
+ ;; CHECK-NEXT: (local.get $z)
+ ;; CHECK-NEXT: (local.get $x)
+ ;; CHECK-NEXT: (local.get $y)
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ ;; CHECK-NEXT: )
+ (func $ternary-identical-arms-call (param $x i32) (param $y i32) (param $z i32)
+ (if
+ (local.get $z)
+ (call $send-i32
+ (local.get $x)
+ )
+ (call $send-i32
+ (local.get $y)
+ )
+ )
+ )
)
generated by cgit v1.2.3 (git 2.39.1) at 2025-04-21 00:08:45 +0000