Add fix for tryToReplaceShiftLandWithRotateInstruction #4427
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AidanHa
commented
Oct 9, 2019
| @@ -1816,7 +1816,6 @@ OMR::Z::TreeEvaluator::tryToReplaceShiftLandWithRotateInstruction(TR::Node * nod | |||
| // RISBG instructions perform unsigned rotation, so if we are selecting the sign bit via the logical AND we cannot | |||
| // perform a signed shift because we must preserve the sign bit. In general we cannot handle this case because we are | |||
| // not certain our input will be non-negative, hence we must conservatively disallow the optimization in such a case. | |||
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Optimization will not work if the current node is commoned. Fixes eclipseGH-4298 Signed-off-by: Aidan Ha <qbha@edu.uwaterloo.ca>
fjeremic
approved these changes
Oct 9, 2019
fjeremic
changed the title
|
@genie-omr build zlinux,zos |
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If the node entered is a common node, then there is no guarantee that the child of the common node will still be alive. And when we try to access the value in that node, we might receive values from a node that might've been killed already. Thus, The optimization will not work.
Fixes GH-4298