Is there a pass to solve the following dead code？

[fa1conn]

for example

      if (Integer.parseInt("0") != 0) {
          i8 = 0;
          i7 = 0;
          columnName = null;
      } else {
          i7 = 28;
          i8 = 93;
      }

[ssj933]

We don't have a pass currently do this. Seems like something that can be added to constant propagation.

[NTillmann]

This commit can serve as a template for how you could plug logic for Integer.parseInt: 25593e1

[fa1conn]

This commit can serve as a template for how you could plug logic for Integer.parseInt: 25593e1

Thanks，I used newest redex to test the String.equals by using ConstantPropagationPass, but it doesn't work. How to make it work?

[fa1conn]

This commit can serve as a template for how you could plug logic for Integer.parseInt: 25593e1

For Boolean.valueOf, It is Effective by using CommonSubexpressionEliminationPass.
For String.equals, It maybe Effective by using peepholePass. It depond on bytecode order matching. If there is some bytecode that interferes with the order it will not be recognized.
And I used ConstantPropagationPass, I found it It doesn't call StringAnalyzer::analyze_invoke function. Does it require additional configuration, or what conditions need to be met to trigger it?

[NTillmann]

ConstantPropagationPass, but it doesn't work

Right, good observation. The ConstantPropagationPass only uses the PrimitiveAnalyzer by default. Other more sophisticated passes use multiple analyzers include the StringAnalyzer, e.g. the InterproceduralConstantPropagationPass, and ShrinkerPass (which basically runs several local optimizations concurrently, which is faster than running individual local optimizations sequentially), and many other passes that (can) use shrinking as part of their operations, e.g. the MethodInlinePass, the IntraDexInlinePass.

I'll look into upgrading ConstantPropagationPass and will report back on that.

[NTillmann]

This would upgrade ConstantPropagationPass to also use the StringAnalyzer (and various other analyzers): #733

However, by itself, it doesn't seem to add much value, just makes the build a bit slower, and by changing some local decisions it may regress the final size a bit. So I am not planning on merging that right now. But you could use it locally if it helps you.

[fa1conn]

This would upgrade ConstantPropagationPass to also use the StringAnalyzer (and various other analyzers): #733

However, by itself, it doesn't seem to add much value, just makes the build a bit slower, and by changing some local decisions it may regress the final size a bit. So I am not planning on merging that right now. But you could use it locally if it helps you.

Thank you very much!