197398 2019-04-29 17:59:21 -0700 [B3] Tails of size 1 can be safely duplicated regardless of their number of predecessors 2019-05-03 10:53:18 -0700 1 1 1 Unclassified WebKit JavaScriptCore WebKit Nightly Build Unspecified Unspecified RESOLVED INVALID P2 Trivial --- 1 rmorisset rmorisset ews-watchlist keith_miller mark.lam msaboff saam oldest_to_newest 1531394 0 rmorisset 2019-04-29 17:59:21 -0700 Replacing a jump (one instruction) by a branch/switch/return (whatever the jump points to, also one instruction) cannot increase the number of instructions, and can be helpful to to things like foldPathConstants that run just after duplicateTails. In most cases we already do this, as the block will have few predecessors, but we should do it unconditionally. The benefit is almost certainly negligible (a quick experiment shows we only neglect to do this optimization 23 times on all of JetStream2), but the change is microscopic too (literally just one line). 1531396 1 368524 rmorisset 2019-04-29 18:03:13 -0700 Created attachment 368524 Patch 1531397 2 368524 rmorisset 2019-04-29 18:14:04 -0700 Comment on attachment 368524 Patch Forget it, I got confused between successors and predecessors, this check does not do at all what I thought. 368524 2019-04-29 18:03:13 -0700 2019-04-29 18:14:04 -0700 Patch patch197398 text/plain 1305 rmorisset ZGlmZiAtLWdpdCBhL1NvdXJjZS9KYXZhU2NyaXB0Q29yZS9DaGFuZ2VMb2cgYi9Tb3VyY2UvSmF2 YVNjcmlwdENvcmUvQ2hhbmdlTG9nCmluZGV4IDI4YWVjYTQ2MGNhLi4zMTcyY2VlZWIyNyAxMDA2 NDQKLS0tIGEvU291cmNlL0phdmFTY3JpcHRDb3JlL0NoYW5nZUxvZworKysgYi9Tb3VyY2UvSmF2 YVNjcmlwdENvcmUvQ2hhbmdlTG9nCkBAIC0xLDMgKzEsMTIgQEAKKzIwMTktMDQtMjkgIFJvYmlu IE1vcmlzc2V0ICA8cm1vcmlzc2V0QGFwcGxlLmNvbT4KKworICAgICAgICBbQjNdIFRhaWxzIG9m IHNpemUgMSBjYW4gYmUgc2FmZWx5IGR1cGxpY2F0ZWQgcmVnYXJkbGVzcyBvZiB0aGVpciBudW1i ZXIgb2YgcHJlZGVjZXNzb3JzCisgICAgICAgIGh0dHBzOi8vYnVncy53ZWJraXQub3JnL3Nob3df YnVnLmNnaT9pZD0xOTczOTgKKworICAgICAgICBSZXZpZXdlZCBieSBOT0JPRFkgKE9PUFMhKS4K KworICAgICAgICAqIGIzL0IzRHVwbGljYXRlVGFpbHMuY3BwOgorCiAyMDE5LTA0LTI2ICBLZWl0 aCBSb2xsaW4gIDxrcm9sbGluQGFwcGxlLmNvbT4KIAogICAgICAgICBFbmFibGUgbmV3IGJ1aWxk IHJ1bGUgZm9yIHBvc3QtcHJvY2Vzc2luZyBoZWFkZXJzIHdoZW4gdXNpbmcgWENCdWlsZApkaWZm IC0tZ2l0IGEvU291cmNlL0phdmFTY3JpcHRDb3JlL2IzL0IzRHVwbGljYXRlVGFpbHMuY3BwIGIv U291cmNlL0phdmFTY3JpcHRDb3JlL2IzL0IzRHVwbGljYXRlVGFpbHMuY3BwCmluZGV4IGNmZjQ0 YTRjMWUwLi40YTk0OGE0NGQwYiAxMDA2NDQKLS0tIGEvU291cmNlL0phdmFTY3JpcHRDb3JlL2Iz L0IzRHVwbGljYXRlVGFpbHMuY3BwCisrKyBiL1NvdXJjZS9KYXZhU2NyaXB0Q29yZS9iMy9CM0R1 cGxpY2F0ZVRhaWxzLmNwcApAQCAtNzUsNyArNzUsNyBAQCBwdWJsaWM6CiAgICAgICAgIGZvciAo QmFzaWNCbG9jayogYmxvY2sgOiBtX3Byb2MpIHsKICAgICAgICAgICAgIGlmIChibG9jay0+c2l6 ZSgpID4gbV9tYXhTaXplKQogICAgICAgICAgICAgICAgIGNvbnRpbnVlOwotICAgICAgICAgICAg aWYgKGJsb2NrLT5udW1TdWNjZXNzb3JzKCkgPiBtX21heFN1Y2Nlc3NvcnMpCisgICAgICAgICAg ICBpZiAoYmxvY2stPm51bVN1Y2Nlc3NvcnMoKSA+IG1fbWF4U3VjY2Vzc29ycyAmJiBibG9jay0+ c2l6ZSgpICE9IDEpCiAgICAgICAgICAgICAgICAgY29udGludWU7CiAgICAgICAgICAgICBpZiAo YmxvY2stPmxhc3QoKS0+dHlwZSgpICE9IFZvaWQpIC8vIERlbW90aW5nIGRvZXNuJ3QgaGFuZGxl IHRlcm1pbmFscyB3aXRoIHZhbHVlcy4KICAgICAgICAgICAgICAgICBjb250aW51ZTsK