Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: b2a5db1e5138d9ee9a25d35696ed8149d47d97ba
https://github.com/WebKit/WebKit/commit/b2a5db1e5138d9ee9a25d35696ed8149d47d97ba
Author: Yusuke Suzuki <[email protected]>
Date: 2026-10-13 (Tue, 13 Oct 2026)
Changed paths:
A JSTests/wasm/stress/struct-get-forwarding-across-dead-arm.js
M Source/JavaScriptCore/b3/B3ReduceStrength.cpp
M Source/JavaScriptCore/b3/testb3.h
M Source/JavaScriptCore/b3/testb3_1.cpp
M Source/JavaScriptCore/b3/testb3_4.cpp
Log Message:
-----------
[JSC] Fold Phis during the B3 ReduceStrength walk and drop the second value
walk
https://bugs.webkit.org/show_bug.cgi?id=326678
rdar://189414617
Reviewed by Dan Hecht.
B3 ReduceStrength's second walk is largely for `Phi` folding which can
be seen due to dropping Branch's edge. This patch does this Phi
optimization much more incrementally while visiting values so that we
avoid the second iteration of ReduceStrength.
We detect unreachable blocks by checking predecessor's visiting state.
Then we remove Upsilon from them, and making Phi simplification work.
* JSTests/wasm/stress/struct-get-forwarding-across-dead-arm.js: Added.
(from.string_appeared_here.import.as.assert.from.string_appeared_here.const.wat.module.type.S.struct.field.mut.i32.func.export.string_appeared_here.param.value.i32.result.ref.S.struct.new.S.local.value.func.deadArm.param.s.ref.S.param.x.i32.result.i32.local.t.i32.local.t.struct.S.0.local.s.i32.and.local.x.i32.const.0.then.struct.S.0.local.s.i32.add.local.t.i32.const.1.i32.add.local.t.struct.S.0.local.s.func.liveArm.param.s.ref.S.param.x.i32.result.i32.local.t.i32.local.t.struct.S.0.local.s.i32.and.local.x.i32.const.1.then.struct.S.0.local.s.i32.add.local.t.i32.const.1.i32.add.local.t.struct.S.0.local.s.func.foldedArm.param.s.ref.S.param.x.i32.result.i32.local.t.i32.local.t.struct.S.0.local.s.i32.or.local.x.i32.const.1.then.struct.S.0.local.s.i32.const.5.i32.add.local.t.struct.S.0.local.s.func.export.string_appeared_here.param.s.ref.S.param.n.i32.result.i32.local.i.i32.local.acc.i32.loop.l.local.acc.i32.add.local.acc.call.deadArm.local.s.local.i.local.i.i32.add.local.i.i32.const.1.br_if.l.i32.lt_u.local.i.local.n.local.acc.func.export.string_appeared_here.param.s.ref.S.param.n.i32.result.i32.local.i.i32.local.acc.i32.loop.l.local.acc.i32.add.local.acc.call.liveArm.local.s.local.i.local.i.i32.add.local.i.i32.const.1.br_if.l.i32.lt_u.local.i.local.n.local.acc.func.export.string_appeared_here.param.s.ref.S.param.n.i32.result.i32.local.i.i32.local.acc.i32.loop.l.local.acc.i32.add.local.acc.call.foldedArm.local.s.local.i.local.i.i32.add.local.i.i32.const.1.br_if.l.i32.lt_u.local.i.local.n.local.acc.async
test):
* Source/JavaScriptCore/b3/B3ReduceStrength.cpp:
* Source/JavaScriptCore/b3/testb3.h:
* Source/JavaScriptCore/b3/testb3_1.cpp:
(run):
* Source/JavaScriptCore/b3/testb3_4.cpp:
(valueCount):
(onlyReturnedValue):
(testPhiFoldChain):
(testPhiFoldKeepsUpsilonBeforeFoldedBranch):
(testPhiFoldUpsilonAwayFromJoin):
(testPhiFoldLoopUnderConstantBranch):
(testPhiFoldLoopInvariantPhis):
(testPhiFoldDeadLoopSelfReference):
(testPhiFoldDeadIrreducibleCycle):
(testPhiFoldDeadLoopFeedingBranch):
(setReturn42Generator):
(testPhiFoldCheckAlwaysExitsBeforePhi):
(testPhiFoldEqualConstantFromBackEdge):
(testPhiFoldDeadLoopWithStalePredecessor):
(testPhiFoldConstantInBlockReachedOnlyByRetreatingEdge):
(testPhiFoldInBlockReachedOnlyByRetreatingEdge):
(testPhiFoldDeadLoopHeaderEnteredFromRoot):
(testPhiFoldLoopPhiTrivialAfterLatch):
Canonical link: https://commits.webkit.org/323635@main
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