dfmc-llvm-back-end: Fix left shift overflow detection #1256
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Did you mean for this to include the testworks channges? They seem like a separate concern. |
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Yes, all other things being equal I like to commit regression tests together with the corresponding bug fixes. |
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I think @waywardmonkeys is referring to the changes to the testworks submodule which you can see here - are they related to the change in hand? |
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Oh, no they are not... updated. |
cgay
reviewed
Sep 25, 2019
| @@ -29,7 +29,19 @@ define test bug-5954 () | |||
| -17); | |||
| end test bug-5954; | |||
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| define test bug-github-1239 () | |||
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Bike shedding: to me it would be better to name the test for what it does, e.g. test-shift-left-signals-overflow, and put the bug URL in a comment. Up to you though.
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Fair enough. Updated again.
This change fixes the previously-incorrect LLVM back-end implementation of the primitive-machine-word-shift-left-signal-overflow primitive. * sources/dfmc/llvm-back-end/llvm-primitives-machine-word.dylan (primitive-machine-word-shift-left-signal-overflow): Check for overflow by counting the number of leading bits identical to the sign bit and insuring that the shift length does not exceed this value. * sources/common-dylan/tests/regressions.dylan (test bug-github-1239): New regression test for ash() overflow detection failures.
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This change fixes the previously-incorrect LLVM back-end
implementation of the primitive-machine-word-shift-left-signal-overflow primitive.
This fixes issue #1239.