Hans Wennborg 5baa764b97 Merging r226755: ...

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r226755 | sanjoy | 2015-01-21 16:48:47 -0800 (Wed, 21 Jan 2015) | 11 lines

Make ScalarEvolution less aggressive with respect to no-wrap flags.

ScalarEvolution currently lowers a subtraction recurrence to an add
recurrence with the same no-wrap flags as the subtraction.  This is
incorrect because `sub nsw X, Y` is not the same as `add nsw X, -Y`
and `sub nuw X, Y` is not the same as `add nuw X, -Y`.  This patch
fixes the issue, and adds two test cases demonstrating the bug.

Differential Revision: http://reviews.llvm.org/D7081


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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_36@226839 91177308-0d34-0410-b5e6-96231b3b80d8

2015-01-22 16:58:19 +00:00

318 KiB

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