Added an inverse fn for Condition#443
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maximecb merged 1 commit intobetter-bcondfrom Aug 31, 2022
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Prevents the need to pass two params and potentially reduces errors.
k0kubun
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Aug 31, 2022
* Better b.cond usage on AArch64 When we're lowering a conditional jump, we previously had a bit of a complicated setup where we could emit a conditional jump to skip over a jump that was the next instruction, and then write out the destination and use a branch register. Now instead we use the b.cond instruction if our offset fits (not common, but not unused either) and if it doesn't we write out an inverse condition to jump past loading the destination and branching directly. * Added an inverse fn for Condition (#443) Prevents the need to pass two params and potentially reduces errors. Co-authored-by: Jimmy Miller <jimmyhmiller@jimmys-mbp.lan> Co-authored-by: Maxime Chevalier-Boisvert <maximechevalierb@gmail.com> Co-authored-by: Jimmy Miller <jimmyhmiller@jimmys-mbp.lan>
noahgibbs
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Sep 1, 2022
| Condition::GT => Condition::LE, | ||
| Condition::LE => Condition::GT, | ||
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| Condition::AL => Condition::AL, |
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In the case of inverting an ALways, presumably you'd get an unexpected result from the code below. Though I don't think you'd ever want to pass it here. So maybe this should panic?
I don't see a "never" type condition code for ARM, so I think inverting an ALways is incorrect/impossible.
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I think you're right Noah. This should panic.
…On Thu., Sep. 1, 2022, 5:41 a.m. Noah Gibbs, ***@***.***> wrote:
***@***.**** commented on this pull request.
------------------------------
In yjit/src/asm/arm64/arg/condition.rs
<#443 (comment)>:
> + Condition::MI => Condition::PL,
+ Condition::PL => Condition::MI,
+
+ Condition::VS => Condition::VC,
+ Condition::VC => Condition::VS,
+
+ Condition::HI => Condition::LS,
+ Condition::LS => Condition::HI,
+
+ Condition::LT => Condition::GE,
+ Condition::GE => Condition::LT,
+
+ Condition::GT => Condition::LE,
+ Condition::LE => Condition::GT,
+
+ Condition::AL => Condition::AL,
In the case of inverting an ALways, presumably you'd get an unexpected
result from the code below. Though I don't think you'd ever want to pass it
here. So maybe this should panic?
I don't see a "never" type condition code for ARM, so I think inverting an
ALways is incorrect/impossible.
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Prevents the need to pass two params and potentially reduces errors.