[llvm-dev] vrp (original) (raw)

Anastasiya Ruzhanskaya via llvm-dev llvm-dev at lists.llvm.org
Mon Aug 7 02:14:10 PDT 2017

I am trying to print it like this (maybe here is smth wrong?)

LazyValueInfo &LV = getAnalysis<LazyValueInfoWrapperPass>().getLVI();
DominatorTree &DT =

getAnalysis().getDomTree(); LV.printLVI(F, DT, llvm::outs()); for (BasicBlock &BB : F) { for (Instruction &I : BB) { if (Value* v = dyn_cast(&I)) if (v->getType()->isIntegerTy()) { ConstantRange r = LV.getConstantRange(v, &BB, &I); I.dump(); printf("LOWER VALUE : %llu\n",r.getLower().getRawData()); printf("UPPER VALUE : %llu\n",r.getUpper().getRawData()); } } }

2017-08-07 11:12 GMT+02:00 Anastasiya Ruzhanskaya < anastasiya.ruzhanskaya at frtk.ru>:

Hello, I am trying to figure out, what vrp propagation does in llvm. I tried this program: #include <stdio.h>

int main() { int s = 0; int j = 0; for (int i = 0; i < 100; i++) { j = j+i+1; s+=j; } return (s+j); } And got this under optimized version ( I don't want everything to be eliminated) define i32 @main() #0 { entry: br label %for.body for.body: ; preds = %for.body, %entry %i.03 = phi i32 [ 0, %entry ], [ %inc, %for.body ] %s.02 = phi i32 [ 0, %entry ], [ %add2, %for.body ] %j.01 = phi i32 [ 0, %entry ], [ %add1, %for.body ] %add = add nsw i32 %j.01, %i.03 %add1 = add nsw i32 %add, 1 %add2 = add nsw i32 %s.02, %add1 %inc = add nsw i32 %i.03, 1 %cmp = icmp slt i32 %i.03, 99 br i1 %cmp, label %for.body, label %for.end for.end: ; preds = %for.body %add3 = add nsw i32 %add2, %add1 ret i32 %add3 }

the value range pass was not able to determine any size, even of the induction variable, is it a correct behavior? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20170807/b182e169/attachment.html>

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