| Summary: | Implement support for op_negate and op_bitnot in the DFG JIT. | ||||||||||
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| Product: | WebKit | Reporter: | Gavin Barraclough <barraclough> | ||||||||
| Component: | JavaScriptCore | Assignee: | Gavin Barraclough <barraclough> | ||||||||
| Status: | RESOLVED FIXED | ||||||||||
| Severity: | Normal | CC: | fpizlo, ggaren, sam | ||||||||
| Priority: | P2 | ||||||||||
| Version: | 528+ (Nightly build) | ||||||||||
| Hardware: | Unspecified | ||||||||||
| OS: | Unspecified | ||||||||||
| Attachments: |
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Description
Gavin Barraclough
2012-02-26 19:04:40 PST
Created attachment 128955 [details]
Fix
Gah, just finished testing, there is a bug here. To implement negate as a subtract, it is -0.0 - X, rather than 0 - X, d'oh, should have remembered that. Optimizing this would probably going to mean adding special cases for subtract-from-negative-zero throughout the code, so it's probably easier to just keep op_negate, and add support to the DFG JIT. In the case of op_bitnot, removing this was a nice simplification so I'll probably stick with that approach. Created attachment 129064 [details]
Remove op_bitnot
Comment on attachment 129064 [details] Remove op_bitnot View in context: https://bugs.webkit.org/attachment.cgi?id=129064&action=review > Source/JavaScriptCore/ChangeLog:8 > + Remove op_bitnop รข this is redundant, ~x === x^-1. Weird unicode character. > Source/JavaScriptCore/ChangeLog:10 > + Please put a comment about removing the canUse part of ResultType. Created attachment 129110 [details]
ArithNegate
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