Bug 242816

Summary: [JSC] Improve same-register moves in AirAllocateRegistersAndStackAndGenerateCode
Product: WebKit Reporter: Joseph Griego <joseph.j.griego>
Component: JavaScriptCoreAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal CC: webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   

Description Joseph Griego 2022-07-15 13:00:25 PDT 
When we are emitting a `Move` from a Tmp to a named-register Tmp that matches
its current allocation, we currently generate code that spills the source tmp to
the stack, allocates a new (distinct) register for it, restores it there, and
then moves it; this seems wasteful and, although this kind of situation in Air
is not common on x86_64, we do generate it on 32-bit ARM targets
Comment 1 Joseph Griego 2022-07-15 13:04:08 PDT 
Pull request: https://github.com/WebKit/WebKit/pull/2462
Comment 2 Radar WebKit Bug Importer 2022-07-22 13:01:17 PDT 
<rdar://problem/97452075>