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Cranelift: regalloc2: use clobbers rather than phantom defs for calls. #4027

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cfallin opened this issue Apr 14, 2022 · 1 comment
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Cranelift: regalloc2: use clobbers rather than phantom defs for calls. #4027

cfallin opened this issue Apr 14, 2022 · 1 comment
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cranelift:area:regalloc Issues related to register allocation. cranelift Issues related to the Cranelift code generator enhancement

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cfallin commented Apr 14, 2022

The initial switchover to regalloc2 retains the mechanism by which calls signal clobbered physical registers, namely, via phantom defs (defs that are immediately dead and are constrained to those regs). regalloc2 has an explicit mechanism for clobbers which is a bit more precise and possibly ever-so-slightly faster (skips liveness analysis); we should use that instead. No functional correctness implications either way.
@cfallin cfallin mentioned this issue Apr 14, 2022
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@akirilov-arm akirilov-arm added enhancement cranelift Issues related to the Cranelift code generator cranelift:area:regalloc Issues related to register allocation. labels May 10, 2022
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cfallin commented Aug 2, 2022

Cleaning up old issues: this was actually fixed in #4324.

@cfallin cfallin closed this as completed Aug 2, 2022
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cranelift:area:regalloc Issues related to register allocation. cranelift Issues related to the Cranelift code generator enhancement
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