RESOLVED FIXED 136569
offlineasm generates suboptimal code for load/store on ARM64 
https://bugs.webkit.org/show_bug.cgi?id=136569
Summary offlineasm generates suboptimal code for load/store on ARM64
Akos Kiss
Reported 2014-09-05 03:16:13 PDT
For every load/store instruction, where the address is in the form of base + offset, and the offset is out of range -255..4095, the ARM64 backend applies the standard risc lowering. That is, as the documentation of riscLowerMalformedAddresses describes: loadp 10000[foo], bar will become move 10000, tmp addp foo, tmp loadp 0[tmp], bar Which, in ARM64, means that, e.g., storep cfr, VM::topVMEntryFrame[vm] becomes movz x17, #45424, lsl #0 add x17, x17, x1 str x29, [x17, #0] However, ARM64 can do better: movz x17, #45424, lsl #0 str x29, [x1, x17, lsl #0] This would achieve the same result with less instructions.
Attachments
Proposed patch. (3.41 KB, patch)
2014-09-05 04:33 PDT, Akos Kiss 		msaboff: review+
DetailsFormatted DiffDiff
Updated patch (3.42 KB, patch)
2014-09-10 15:37 PDT, Akos Kiss 		no flags
DetailsFormatted DiffDiff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.
Akos Kiss
Comment 1 2014-09-05 04:33:42 PDT
Created attachment 237682 [details] Proposed patch.
Michael Saboff
Comment 2 2014-09-10 14:06:14 PDT
Comment on attachment 237682 [details] Proposed patch. View in context: https://bugs.webkit.org/attachment.cgi?id=237682&action=review r=me > Source/JavaScriptCore/ChangeLog:10 > + base to the temporary, and the change the load/store to use the "the change" -> "then change" > Source/JavaScriptCore/ChangeLog:13 > + perform explicit register additons but it is enough to change load/store Typo: "additions"
Michael Saboff
Comment 3 2014-09-10 14:07:48 PDT
Comment on attachment 237682 [details] Proposed patch. r=me
Akos Kiss
Comment 4 2014-09-10 15:37:27 PDT
Created attachment 237911 [details] Updated patch Typos fixed.
Michael Saboff
Comment 5 2014-09-10 16:00:25 PDT
Comment on attachment 237911 [details] Updated patch r=me.
WebKit Commit Bot
Comment 6 2014-09-10 16:57:48 PDT
Comment on attachment 237911 [details] Updated patch Clearing flags on attachment: 237911 Committed r173497: <http://trac.webkit.org/changeset/173497>
WebKit Commit Bot
Comment 7 2014-09-10 16:57:51 PDT
All reviewed patches have been landed. Closing bug.
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