68977 2011-09-28 00:04:29 -0700 DFG JIT falls back on numerical comparisons when it does not recognize a prediction 2011-09-28 17:47:56 -0700 1 1 1 Unclassified WebKit JavaScriptCore 528+ (Nightly build) All All RESOLVED FIXED P2 Normal --- 1 fpizlo webkit-unassigned oldest_to_newest 474550 0 fpizlo 2011-09-28 00:04:29 -0700 The DFG will emit numerical comparison code (with numerical speculation) when the operands to the comparison are something that it does not have optimized code generation for. This means that any code that tries to compare strings, for example, will fall out of the speculative path. 475032 1 109080 fpizlo 2011-09-28 14:58:35 -0700 Created attachment 109080 the patch 475036 2 109080 ggaren 2011-09-28 15:01:26 -0700 Comment on attachment 109080 the patch r=me Can double comparisons peephole fuse with branches? 475037 3 109080 oliver 2011-09-28 15:03:06 -0700 Comment on attachment 109080 the patch Add test cases that hit the object equality instead of correct operation case. 475127 4 fpizlo 2011-09-28 17:47:34 -0700 (In reply to comment #2) > (From update of attachment 109080 [details]) > r=me > > Can double comparisons peephole fuse with branches? Yup. We drop through the shouldSpeculateInteger() check, and then trigger on the shouldSpeculateNumber() check (which means are these things either double or integer, plus still some cruft from static speculation days, which I'll get rid of eventually in another patch). 475129 5 fpizlo 2011-09-28 17:47:56 -0700 Landed in r96280. 109080 2011-09-28 14:58:35 -0700 2011-09-28 15:03:05 -0700 the patch bettercompare_patch_1.diff text/plain 3999 fpizlo SW5kZXg6IFNvdXJjZS9KYXZhU2NyaXB0Q29yZS9DaGFuZ2VMb2cKPT09PT09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PQotLS0gU291 cmNlL0phdmFTY3JpcHRDb3JlL0NoYW5nZUxvZwkocmV2aXNpb24gOTYyNjIpCisrKyBTb3VyY2Uv SmF2YVNjcmlwdENvcmUvQ2hhbmdlTG9nCSh3b3JraW5nIGNvcHkpCkBAIC0xLDMgKzEsMTggQEAK KzIwMTEtMDktMjggIEZpbGlwIFBpemxvICA8ZnBpemxvQGFwcGxlLmNvbT4KKworICAgICAgICBE RkcgSklUIGZhbGxzIGJhY2sgb24gbnVtZXJpY2FsIGNvbXBhcmlzb25zIHdoZW4gaXQgZG9lcyBu b3QKKyAgICAgICAgcmVjb2duaXplIGEgcHJlZGljdGlvbgorICAgICAgICBodHRwczovL2J1Z3Mu 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