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[WebAssembly] Demote PHIs in catchswitch BB only #81570

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Merged
merged 1 commit into from
Feb 13, 2024
Merged

[WebAssembly] Demote PHIs in catchswitch BB only #81570

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3 changes: 2 additions & 1 deletion llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
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Expand Up @@ -249,7 +249,8 @@ void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf,
"WinEHPrepare failed to remove PHIs from imaginary BBs");
continue;
}
if (isa<FuncletPadInst>(PadInst))
if (isa<FuncletPadInst>(PadInst) &&
Personality != EHPersonality::Wasm_CXX)
assert(&*BB.begin() == PadInst && "WinEHPrepare failed to demote PHIs");
}

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2 changes: 1 addition & 1 deletion llvm/lib/CodeGen/TargetPassConfig.cpp
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Expand Up @@ -918,7 +918,7 @@ void TargetPassConfig::addPassesToHandleExceptions() {
// on catchpads and cleanuppads because it does not outline them into
// funclets. Catchswitch blocks are not lowered in SelectionDAG, so we
// should remove PHIs there.
addPass(createWinEHPass(/*DemoteCatchSwitchPHIOnly=*/false));
addPass(createWinEHPass(/*DemoteCatchSwitchPHIOnly=*/true));
addPass(createWasmEHPass());
break;
case ExceptionHandling::None:
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2 changes: 1 addition & 1 deletion llvm/test/CodeGen/WebAssembly/wasm-eh-prepare.ll
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Expand Up @@ -2,6 +2,7 @@
; RUN: opt < %s -win-eh-prepare -demote-catchswitch-only -wasm-eh-prepare -S --mattr=+atomics,+bulk-memory | FileCheck %s
; RUN: opt < %s -passes='win-eh-prepare<demote-catchswitch-only>,wasm-eh-prepare' -S | FileCheck %s
; RUN: opt < %s -passes='win-eh-prepare<demote-catchswitch-only>,wasm-eh-prepare' -S --mattr=+atomics,+bulk-memory | FileCheck %s
; RUN: llc < %s -wasm-enable-eh -exception-model=wasm -mattr=+exception-handling -stop-after=wasm-eh-prepare | FileCheck %s
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So far this was missed because we've been only running opt tests, with which we run -win-eh-prepare with -demote-catchswitch-only option manually. This adds a llc test that uses TargetPassConfig.cpp.


target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
target triple = "wasm32-unknown-unknown"
Expand Down Expand Up @@ -245,7 +246,6 @@ bb.true: ; preds = %entry
bb.true.0: ; preds = %bb.true
br label %merge

; CHECK: bb.false
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This was deleted because, in llc tests many passes run before WinEHPrepare and WasmEHPrepare, and some of them did some simplification of the CFG, removing this BB.

bb.false: ; preds = %entry
br label %merge

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