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Merged
tlively merged 1 commit into from
Apr 8, 2024
Merged

Handle return calls in CodeFolding #6474

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22 changes: 21 additions & 1 deletion src/passes/CodeFolding.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -172,7 +172,7 @@ struct CodeFolding : public WalkerPass<ControlFlowWalker<CodeFolding>> {
}
}

void visitReturn(Return* curr) {
void handleReturn(Expression* curr) {
if (!controlFlowStack.empty()) {
// we can easily optimize if we are at the end of the parent block
Block* parent = controlFlowStack.back()->dynCast<Block>();
Expand All @@ -186,6 +186,26 @@ struct CodeFolding : public WalkerPass<ControlFlowWalker<CodeFolding>> {
returnTails.push_back(Tail(curr, getCurrentPointer()));
}

void visitReturn(Return* curr) { handleReturn(curr); }

void visitCall(Call* curr) {
if (curr->isReturn) {
handleReturn(curr);
}
}

void visitCallIndirect(CallIndirect* curr) {
if (curr->isReturn) {
handleReturn(curr);
}
}

void visitCallRef(CallRef* curr) {
if (curr->isReturn) {
handleReturn(curr);
}
}

void visitBlock(Block* curr) {
if (curr->list.empty()) {
return;
Expand Down
191 changes: 186 additions & 5 deletions test/lit/passes/code-folding-eh-old.wast
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@
;; CHECK: (tag $e-i32 (param i32))
(tag $e-i32 (param i32))

;; CHECK: (func $pop-test (type $0)
;; CHECK: (func $pop-test (type $1)
;; CHECK-NEXT: (block $folding-inner0
;; CHECK-NEXT: (try
;; CHECK-NEXT: (do
Expand Down Expand Up @@ -67,12 +67,55 @@
)
)

;; CHECK: (func $foo (type $0)
;; CHECK: (func $try-call-optimize-terminating-tails-success (type $0) (result i32)
;; CHECK-NEXT: (block $folding-inner0
;; CHECK-NEXT: (return
;; CHECK-NEXT: (block (result i32)
;; CHECK-NEXT: (try
;; CHECK-NEXT: (do
;; CHECK-NEXT: (br $folding-inner0)
;; CHECK-NEXT: )
;; CHECK-NEXT: (catch_all
;; CHECK-NEXT: (br $folding-inner0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (return
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $try-call-optimize-terminating-tails-success (result i32)
(try
(do
(drop (i32.const 1))
(drop (i32.const 1))
(return (i32.const 0))
)
(catch_all
(drop (i32.const 1))
(drop (i32.const 1))
(return (i32.const 0))
)
)
(i32.const 0)
)
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@kripken kripken Apr 5, 2024

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same question.



;; CHECK: (func $foo (type $1)
;; CHECK-NEXT: (nop)
;; CHECK-NEXT: )
(func $foo)

;; CHECK: (func $try-call-optimize-terminating-tails (type $1) (result i32)
;; CHECK: (func $try-call-optimize-terminating-tails (type $0) (result i32)
;; CHECK-NEXT: (try
;; CHECK-NEXT: (do
;; CHECK-NEXT: (call $foo)
Expand Down Expand Up @@ -116,7 +159,145 @@
(i32.const 0)
)

;; CHECK: (func $try-call-optimize-expression-tails (type $0)
;; CHECK: (func $foo-i32 (type $0) (result i32)
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
(func $foo-i32 (result i32)
(i32.const 0)
)

;; CHECK: (func $try-call-optimize-terminating-tails-call-return (type $0) (result i32)
;; CHECK-NEXT: (try
;; CHECK-NEXT: (do
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (return
;; CHECK-NEXT: (call $foo-i32)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (catch_all
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (return
;; CHECK-NEXT: (call $foo-i32)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
(func $try-call-optimize-terminating-tails-call-return (result i32)
(try
(do
(drop (i32.const 1))
(drop (i32.const 1))
;; Cannot be folded out of the try because it might throw.
(return (call $foo-i32))
)
(catch_all
(drop (i32.const 1))
(drop (i32.const 1))
(return (call $foo-i32))
)
)
(i32.const 0)
)

;; CHECK: (func $try-call-optimize-terminating-tails-return-call (type $0) (result i32)
;; CHECK-NEXT: (block $folding-inner0
;; CHECK-NEXT: (return
;; CHECK-NEXT: (block (result i32)
;; CHECK-NEXT: (try
;; CHECK-NEXT: (do
;; CHECK-NEXT: (br $folding-inner0)
;; CHECK-NEXT: )
;; CHECK-NEXT: (catch_all
;; CHECK-NEXT: (br $folding-inner0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (i32.const 0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (return_call $foo-i32)
;; CHECK-NEXT: )
(func $try-call-optimize-terminating-tails-return-call (result i32)
(try
(do
(drop (i32.const 1))
(drop (i32.const 1))
(drop (i32.const 1))
(return_call $foo-i32)
)
(catch_all
(drop (i32.const 1))
(drop (i32.const 1))
(drop (i32.const 1))
(return_call $foo-i32)
)
)
(i32.const 0)
)

;; CHECK: (func $try-call-optimize-expression-tails-success (type $1)
;; CHECK-NEXT: (block $x
;; CHECK-NEXT: (try
;; CHECK-NEXT: (do
;; CHECK-NEXT: (br $x)
;; CHECK-NEXT: )
;; CHECK-NEXT: (catch_all
;; CHECK-NEXT: (br $x)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (unreachable)
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: (drop
;; CHECK-NEXT: (i32.const 1)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
(func $try-call-optimize-expression-tails-success
(block $x
(try
(do
(drop (i32.const 1))
(drop (i32.const 1))
(drop (i32.const 1))
(br $x)
)
(catch_all
(drop (i32.const 1))
(drop (i32.const 1))
(drop (i32.const 1))
(br $x)
)
)
(unreachable)
)
)
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@kripken kripken Apr 5, 2024

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did we not have a test for this before?

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@tlively tlively Apr 5, 2024

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No, not that I was able to find for either of these tests. Except for the throws effect analysis, the implementation does not seem to special case try-catch at all, so it's reasonable that we wouldn't need tests for the success cases. But when I was trying to debug and figure out how to get this change working, it was useful to prove to myself locally that similar cases did already work correctly.


;; CHECK: (func $try-call-optimize-expression-tails (type $1)
;; CHECK-NEXT: (block $x
;; CHECK-NEXT: (try
;; CHECK-NEXT: (do
Expand Down Expand Up @@ -156,7 +337,7 @@
)
)

;; CHECK: (func $if-arms-in-catch (type $1) (result i32)
;; CHECK: (func $if-arms-in-catch (type $0) (result i32)
;; CHECK-NEXT: (local $0 i32)
;; CHECK-NEXT: (try
;; CHECK-NEXT: (do
Expand Down