C++: Store destinations should not be uses for dataflow SSA #7578
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…ugh phi nodes in IR dataflow.
MathiasVP
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redsun82
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Jan 18, 2022
| load.getAUse().getUse() instanceof InitializeIndirectionInstruction | ||
| ) and | ||
| // Don't include this operand as a use if the only use of the address is for a write | ||
| // that definately overrides a variable. |
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Thanks! Fixed in e1598ab.
rdmarsh2
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Jan 18, 2022
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This PR is basically a glorified cherry-pick of 092beb8. The code was written as a response to one of the reviews on #6825, but the commit had to be reverted because it caused a loss of dataflow on some projects.
I've now looked at those results, and it turns out they were all FPs caused by weird interaction with phi nodes. e8afec4 demonstrates the kind of false-positive that underlies all of the lost results, and 25253c7 fixes the false-positive by doing exactly what 092beb8 did.
Performance on DCA looks fine.