228674 2021-07-30 20:11:42 -0700 [JSC] branchTest8 should not emit tst for Zero/NonZero cases 2021-07-30 23:34:14 -0700 1 1 1 Unclassified WebKit New Bugs WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED InRadar P2 Normal --- 1 ysuzuki ysuzuki ews-watchlist keith_miller mark.lam msaboff saam tzagallo webkit-bug-importer oldest_to_newest 1781041 0 ysuzuki 2021-07-30 20:11:42 -0700 [JSC] branchTest8 should not emit tst for Zero/NonZero cases 1781042 1 434685 ysuzuki 2021-07-30 20:14:51 -0700 Created attachment 434685 Patch 1781043 2 434686 ysuzuki 2021-07-30 20:19:56 -0700 Created attachment 434686 Patch 1781047 3 434686 mark.lam 2021-07-30 21:23:00 -0700 Comment on attachment 434686 Patch View in context: https://bugs.webkit.org/attachment.cgi?id=434686&action=review r=me > Source/JavaScriptCore/ChangeLog:9 > + unnecessary. This is because the mask is truncated into 8bit, which /unnecessary/unnecessarily/. > Source/JavaScriptCore/ChangeLog:14 > + This patch removes this unnecessary truncation since Zero/NonZero does > + not care high bits of mask in branchTest8. I think it's worth pointing out that this is ok because the ResultCondition version of mask8OnCondition() is always used to generate a mask that is only used against a value that is loaded with MacroAssemblerHelpers::load8OnCondition(). For Zero/NonZero conditions, load8OnCondition() will always zero fill the upper bytes. The 0 filled upper bytes will not affect the result of a branch on zero or branch on not zero. 1781049 4 434686 ysuzuki 2021-07-30 21:45:04 -0700 Comment on attachment 434686 Patch View in context: https://bugs.webkit.org/attachment.cgi?id=434686&action=review >> Source/JavaScriptCore/ChangeLog:9 >> + unnecessary. This is because the mask is truncated into 8bit, which > > /unnecessary/unnecessarily/. Fixed. >> Source/JavaScriptCore/ChangeLog:14 >> + not care high bits of mask in branchTest8. > > I think it's worth pointing out that this is ok because the ResultCondition version of mask8OnCondition() is always used to generate a mask that is only used against a value that is loaded with MacroAssemblerHelpers::load8OnCondition(). For Zero/NonZero conditions, load8OnCondition() will always zero fill the upper bytes. The 0 filled upper bytes will not affect the result of a branch on zero or branch on not zero. Sounds good. Added. 1781050 5 ysuzuki 2021-07-30 21:46:38 -0700 Committed r280508 (240140@main): <https://commits.webkit.org/240140@main> 1781051 6 webkit-bug-importer 2021-07-30 21:47:27 -0700 <rdar://problem/81355381> 434685 2021-07-30 20:14:51 -0700 2021-07-30 20:19:55 -0700 Patch bug-228674-20210730201451.patch text/plain 2532 ysuzuki U3VidmVyc2lvbiBSZXZpc2lvbjogMjgwNTA3CmRpZmYgLS1naXQgYS9Tb3VyY2UvSmF2YVNjcmlw dENvcmUvQ2hhbmdlTG9nIGIvU291cmNlL0phdmFTY3JpcHRDb3JlL0NoYW5nZUxvZwppbmRleCBl M2EyZjE5MTc1NTExMTIzZWIyNTNlNmRjMTcyOTkwMGI4MzkwMTQzLi4zYTI5M2I4ODNiMWRjNzYz YTBlM2Y2ZDViNjBkYmIwZmQyOWFiM2Y4IDEwMDY0NAotLS0gYS9Tb3VyY2UvSmF2YVNjcmlwdENv cmUvQ2hhbmdlTG9nCisrKyBiL1NvdXJjZS9KYXZhU2NyaXB0Q29yZS9DaGFuZ2VMb2cKQEAgLTEs MyArMSwyOSBAQAorMjAyMS0wNy0zMCAgWXVzdWtlIFN1enVraSAgPHlzdXp1a2lAYXBwbGUuY29t PgorCisgICAgICAgIFtKU0NdIGJyYW5jaFRlc3Q4IHNob3VsZCBub3QgZW1pdCB0c3QgZm9yIFpl cm8vTm9uWmVybyBjYXNlcworICAgICAgICBodHRwczovL2J1Z3Mud2Via2l0Lm9yZy9zaG93X2J1 Zy5jZ2k/aWQ9MjI4Njc0CisKKyAgICAgICAgUmV2aWV3ZWQgYnkgTk9CT0RZIChPT1BTISkuCisK KyAgICAgICAgUHJldmlvdXNseSwgYnJhbmNoVGVzdDgoTm9uWmVybywgQmFzZUluZGV4KSBlbWl0 cyBgdHN0YCBpbnN0cnVjdGlvbgorICAgICAgICB1bm5lY2Vzc2FyeS4gVGhpcyBpcyBiZWNhdXNl IHRoZSBtYXNrIGlzIHRydW5jYXRlZCBpbnRvIDhiaXQsIHdoaWNoCisgICAgICAgIG1ha2VzIGJy YW5jaFRlc3QzMiAod2hpY2ggaXMgaW50ZXJuYWxseSB1c2VkIGluIGJyYW5jaFRlc3Q4KSBlbWl0 cyB0c3QuCisKKyAgICAgICAgVGhpcyBwYXRjaCByZW1vdmVzIHRoaXMgdW5uZWNlc3NhcnkgdHJ1 bmNhdGlvbiBzaW5jZSBaZXJvL05vblplcm8gZG9lcworICAgICAgICBub3QgY2FyZSBoaWdoIGJp dHMgb2YgbWFzayBpbiBicmFuY2hUZXN0OC4KKworICAgICAgICBCZWZvcmU6CisgICAgICAgICAg IDB4MTBhODA2OGIwOiAgICBsZHJiICAgICB3MTYsIFt4NywgeDZdCisgICAgICAgICAgIDB4MTBh ODA2OGI0OiAgICB0c3QgICAgICB3MTYsICMweGZmCisgICAgICAgICAgIDB4MTBhODA2OGI4OiAg ICBiLm5lICAgMHgxMGE4MDY4Y2MKKworICAgICAgICBBZnRlcjoKKyAgICAgICAgICAgMHgxMDcw MDY4YjA6ICAgIGxkcmIgICAgIHcxNiwgW3g3LCB4Nl0KKyAgICAgICAgICAgMHgxMDcwMDY4YjQ6 ICAgIGNibnogICAgIHcxNiwgMHgxMDcwMDY4YzgKKworICAgICAgICAqIGFzc2VtYmxlci9NYWNy b0Fzc2VtYmxlckhlbHBlcnMuaDoKKyAgICAgICAgKEpTQzo6TWFjcm9Bc3NlbWJsZXJIZWxwZXJz OjptYXNrOE9uQ29uZGl0aW9uKToKKwogMjAyMS0wNy0zMCAgUm9iaW4gTW9yaXNzZXQgIDxybW9y aXNzZXRAYXBwbGUuY29tPgogCiAgICAgICAgIEltcHJvdmUgT1NSIGVudHJ5IGludG8gV2FzbSBs b29wcyB3aXRoIGFyZ3VtZW50cwpkaWZmIC0tZ2l0IGEvU291cmNlL0phdmFTY3JpcHRDb3JlL2Fz c2VtYmxlci9NYWNyb0Fzc2VtYmxlckhlbHBlcnMuaCBiL1NvdXJjZS9KYXZhU2NyaXB0Q29yZS9h c3NlbWJsZXIvTWFjcm9Bc3NlbWJsZXJIZWxwZXJzLmgKaW5kZXggMDQ3ZTk0YzI3MWIzMDgwNTUw YmM0MjY5M2RkYTQyMzc1MGFjMzJmMS4uZGQ3NjY0OWQwMGFhYWFlNzQ5ZTEyMjFiMjMwODU5YThl Yzk1ODIzOCAxMDA2NDQKLS0tIGEvU291cmNlL0phdmFTY3JpcHRDb3JlL2Fzc2VtYmxlci9NYWNy b0Fzc2VtYmxlckhlbHBlcnMuaAorKysgYi9Tb3VyY2UvSmF2YVNjcmlwdENvcmUvYXNzZW1ibGVy L01hY3JvQXNzZW1ibGVySGVscGVycy5oCkBAIC0xMTMsNiArMTEzLDkgQEAgaW5saW5lIHR5cGVu YW1lIE1hY3JvQXNzZW1ibGVyVHlwZTo6VHJ1c3RlZEltbTMyIG1hc2s4T25Db25kaXRpb24oTWFj cm9Bc3NlbWJsZXIKIHRlbXBsYXRlPHR5cGVuYW1lIE1hY3JvQXNzZW1ibGVyVHlwZT4KIGlubGlu ZSB0eXBlbmFtZSBNYWNyb0Fzc2VtYmxlclR5cGU6OlRydXN0ZWRJbW0zMiBtYXNrOE9uQ29uZGl0 aW9uKE1hY3JvQXNzZW1ibGVyVHlwZSYsIHR5cGVuYW1lIE1hY3JvQXNzZW1ibGVyVHlwZTo6UmVz dWx0Q29uZGl0aW9uIGNvbmQsIHR5cGVuYW1lIE1hY3JvQXNzZW1ibGVyVHlwZTo6VHJ1c3RlZElt bTMyIHZhbHVlKQogeworICAgIC8vIElmIGNvbmRpdGlvbiBpcyBaZXJvIG9yIE5vblplcm8sIHVw cGVyIGJpdHMgYXJlIHVucmVsYXRlZC4gV2UgY2FuIGp1c3QgcmV0dXJuIGdpdmVuIG1hc2sgYXMg aXMuCisgICAgaWYgKGNvbmQgPT0gTWFjcm9Bc3NlbWJsZXJUeXBlOjpaZXJvIHx8IGNvbmQgPT0g TWFjcm9Bc3NlbWJsZXJUeXBlOjpOb25aZXJvKQorICAgICAgICByZXR1cm4gdmFsdWU7CiAgICAg aWYgKGlzVW5zaWduZWQ8TWFjcm9Bc3NlbWJsZXJUeXBlPihjb25kKSkKICAgICAgICAgcmV0dXJu IHR5cGVuYW1lIE1hY3JvQXNzZW1ibGVyVHlwZTo6VHJ1c3RlZEltbTMyKHN0YXRpY19jYXN0PHVp bnQ4X3Q+KHZhbHVlLm1fdmFsdWUpKTsKICAgICBBU1NFUlRfV0lUSF9NRVNTQUdFKGNvbmQgIT0g TWFjcm9Bc3NlbWJsZXJUeXBlOjpPdmVyZmxvdywgIk92ZXJmbG93IGlzIG5vdCB1c2VkIGZvciA4 Yml0IHRlc3Qgb3BlcmF0aW9ucy4iKTsK 434686 2021-07-30 20:19:56 -0700 2021-07-30 23:34:14 -0700 Patch bug-228674-20210730201956.patch text/plain 2709 ysuzuki U3VidmVyc2lvbiBSZXZpc2lvbjogMjgwNTA3CmRpZmYgLS1naXQgYS9Tb3VyY2UvSmF2YVNjcmlw dENvcmUvQ2hhbmdlTG9nIGIvU291cmNlL0phdmFTY3JpcHRDb3JlL0NoYW5nZUxvZwppbmRleCBl M2EyZjE5MTc1NTExMTIzZWIyNTNlNmRjMTcyOTkwMGI4MzkwMTQzLi4xOGNjYzBiYjhkMzUyYzY0 Y2MxM2VmOThjMDQ4YjJjOGVjY2MxY2RjIDEwMDY0NAotLS0gYS9Tb3VyY2UvSmF2YVNjcmlwdENv cmUvQ2hhbmdlTG9nCisrKyBiL1NvdXJjZS9KYXZhU2NyaXB0Q29yZS9DaGFuZ2VMb2cKQEAgLTEs MyArMSwzMCBAQAorMjAyMS0wNy0zMCAgWXVzdWtlIFN1enVraSAgPHlzdXp1a2lAYXBwbGUuY29t PgorCisgICAgICAgIFtKU0NdIGJyYW5jaFRlc3Q4IHNob3VsZCBub3QgZW1pdCB0c3QgZm9yIFpl cm8vTm9uWmVybyBjYXNlcworICAgICAgICBodHRwczovL2J1Z3Mud2Via2l0Lm9yZy9zaG93X2J1 Zy5jZ2k/aWQ9MjI4Njc0CisKKyAgICAgICAgUmV2aWV3ZWQgYnkgTk9CT0RZIChPT1BTISkuCisK KyAgICAgICAgUHJldmlvdXNseSwgYnJhbmNoVGVzdDgoTm9uWmVybywgQmFzZUluZGV4KSBlbWl0 cyBgdHN0YCBpbnN0cnVjdGlvbgorICAgICAgICB1bm5lY2Vzc2FyeS4gVGhpcyBpcyBiZWNhdXNl IHRoZSBtYXNrIGlzIHRydW5jYXRlZCBpbnRvIDhiaXQsIHdoaWNoCisgICAgICAgIG1ha2VzIGJy YW5jaFRlc3QzMiAod2hpY2ggaXMgaW50ZXJuYWxseSB1c2VkIGluIGJyYW5jaFRlc3Q4KSBlbWl0 cyB0c3QuCisgICAgICAgIFdlIG9ic2VydmVkIG1hbnkgdW5uZWNlc3NhcnkgdHN0IGluIFlhcnJK SVQuCisKKyAgICAgICAgVGhpcyBwYXRjaCByZW1vdmVzIHRoaXMgdW5uZWNlc3NhcnkgdHJ1bmNh dGlvbiBzaW5jZSBaZXJvL05vblplcm8gZG9lcworICAgICAgICBub3QgY2FyZSBoaWdoIGJpdHMg b2YgbWFzayBpbiBicmFuY2hUZXN0OC4KKworICAgICAgICBCZWZvcmU6CisgICAgICAgICAgIDB4 MTBhODA2OGIwOiAgICBsZHJiICAgICB3MTYsIFt4NywgeDZdCisgICAgICAgICAgIDB4MTBhODA2 OGI0OiAgICB0c3QgICAgICB3MTYsICMweGZmCisgICAgICAgICAgIDB4MTBhODA2OGI4OiAgICBi Lm5lICAgMHgxMGE4MDY4Y2MKKworICAgICAgICBBZnRlcjoKKyAgICAgICAgICAgMHgxMDcwMDY4 YjA6ICAgIGxkcmIgICAgIHcxNiwgW3g3LCB4Nl0KKyAgICAgICAgICAgMHgxMDcwMDY4YjQ6ICAg IGNibnogICAgIHcxNiwgMHgxMDcwMDY4YzgKKworICAgICAgICAqIGFzc2VtYmxlci9NYWNyb0Fz c2VtYmxlckhlbHBlcnMuaDoKKyAgICAgICAgKEpTQzo6TWFjcm9Bc3NlbWJsZXJIZWxwZXJzOjpt YXNrOE9uQ29uZGl0aW9uKToKKwogMjAyMS0wNy0zMCAgUm9iaW4gTW9yaXNzZXQgIDxybW9yaXNz ZXRAYXBwbGUuY29tPgogCiAgICAgICAgIEltcHJvdmUgT1NSIGVudHJ5IGludG8gV2FzbSBsb29w cyB3aXRoIGFyZ3VtZW50cwpkaWZmIC0tZ2l0IGEvU291cmNlL0phdmFTY3JpcHRDb3JlL2Fzc2Vt Ymxlci9NYWNyb0Fzc2VtYmxlckhlbHBlcnMuaCBiL1NvdXJjZS9KYXZhU2NyaXB0Q29yZS9hc3Nl bWJsZXIvTWFjcm9Bc3NlbWJsZXJIZWxwZXJzLmgKaW5kZXggMDQ3ZTk0YzI3MWIzMDgwNTUwYmM0 MjY5M2RkYTQyMzc1MGFjMzJmMS4uNTQ0ZjE5ODg0MjMxNWI5Y2RjMDNiZjQxY2Y5YzMzMTAzM2Rh ZDgwMCAxMDA2NDQKLS0tIGEvU291cmNlL0phdmFTY3JpcHRDb3JlL2Fzc2VtYmxlci9NYWNyb0Fz c2VtYmxlckhlbHBlcnMuaAorKysgYi9Tb3VyY2UvSmF2YVNjcmlwdENvcmUvYXNzZW1ibGVyL01h Y3JvQXNzZW1ibGVySGVscGVycy5oCkBAIC0xMTMsNiArMTEzLDEyIEBAIGlubGluZSB0eXBlbmFt ZSBNYWNyb0Fzc2VtYmxlclR5cGU6OlRydXN0ZWRJbW0zMiBtYXNrOE9uQ29uZGl0aW9uKE1hY3Jv QXNzZW1ibGVyCiB0ZW1wbGF0ZTx0eXBlbmFtZSBNYWNyb0Fzc2VtYmxlclR5cGU+CiBpbmxpbmUg dHlwZW5hbWUgTWFjcm9Bc3NlbWJsZXJUeXBlOjpUcnVzdGVkSW1tMzIgbWFzazhPbkNvbmRpdGlv bihNYWNyb0Fzc2VtYmxlclR5cGUmLCB0eXBlbmFtZSBNYWNyb0Fzc2VtYmxlclR5cGU6OlJlc3Vs dENvbmRpdGlvbiBjb25kLCB0eXBlbmFtZSBNYWNyb0Fzc2VtYmxlclR5cGU6OlRydXN0ZWRJbW0z MiB2YWx1ZSkKIHsKKyAgICAvLyBJZiBjb25kaXRpb24gaXMgWmVybyBvciBOb25aZXJvLCB1cHBl ciBiaXRzIGFyZSB1bnJlbGF0ZWQuCisgICAgLy8gU2luY2UgYnJhbmNoVGVzdDMyIGhhbmRsZXMg LTEgaW4gYW4gb3B0aW1pemVkIG1hbm5lciwgd2Uga2VlcCAtMSBhcyBpcyBpbnN0ZWFkIG9mIGNv bnZlcnRpbmcgaXQgdG8gMjU1LgorICAgIGlmIChjb25kID09IE1hY3JvQXNzZW1ibGVyVHlwZTo6 WmVybyB8fCBjb25kID09IE1hY3JvQXNzZW1ibGVyVHlwZTo6Tm9uWmVybykgeworICAgICAgICBp ZiAodmFsdWUubV92YWx1ZSA9PSAtMSkKKyAgICAgICAgICAgIHJldHVybiB2YWx1ZTsKKyAgICB9 CiAgICAgaWYgKGlzVW5zaWduZWQ8TWFjcm9Bc3NlbWJsZXJUeXBlPihjb25kKSkKICAgICAgICAg cmV0dXJuIHR5cGVuYW1lIE1hY3JvQXNzZW1ibGVyVHlwZTo6VHJ1c3RlZEltbTMyKHN0YXRpY19j YXN0PHVpbnQ4X3Q+KHZhbHVlLm1fdmFsdWUpKTsKICAgICBBU1NFUlRfV0lUSF9NRVNTQUdFKGNv bmQgIT0gTWFjcm9Bc3NlbWJsZXJUeXBlOjpPdmVyZmxvdywgIk92ZXJmbG93IGlzIG5vdCB1c2Vk IGZvciA4Yml0IHRlc3Qgb3BlcmF0aW9ucy4iKTsK