search for: pr17452

...r example, I’d like to query the range of values that a variable can hold before the loop hits undefined behavior. I don’t know how to implement something like this yet. Ideas are welcome. > > Reading this code again, even the addition case looks too aggressive to me. > See: > llvm.org/PR17452 - SCEV createNodeForPHI is too optimistic about NSW. > If the behavior is different between 'add nsw' and 'sub nsw' then the SCEV canonicalization of 'sub' leads to incorrect results. In your example both result should be the same but the 'add' produces a poiso...

...ike to query the range of values that a variable can hold before the loop hits undefined behavior. I don’t know how to implement something like this yet. Ideas are welcome. >> >> Reading this code again, even the addition case looks too aggressive to me. >> See: >> llvm.org/PR17452 - SCEV createNodeForPHI is too optimistic about NSW. >> > > If the behavior is different between 'add nsw' and 'sub nsw' then the SCEV > canonicalization of 'sub' leads to incorrect results. Creating a SCEV expression for a sub instruction drops the flags....

...defined behavior. For example, I’d like to query the range of values that a variable can hold before the loop hits undefined behavior. I don’t know how to implement something like this yet. Ideas are welcome. Reading this code again, even the addition case looks too aggressive to me. See: llvm.org/PR17452 - SCEV createNodeForPHI is too optimistic about NSW. -Andy

Hello to everybody, I'm working on some improvements on trip count computation with ScalarEvolution analysis. Considering the following test ;----------------------------------------------------------------------------; define void @foo(i32 %a, i32 %b, i32 %s) #0 { entry: %cmp = icmp sgt i32 %s, 0 %cmp15 = icmp sgt i32 %a, %b %or.cond = and i1 %cmp, %cmp15 br i1 %or.cond, label

...like to query the range of values that a variable can hold before the loop hits undefined behavior. I don’t know how to implement something like this yet. Ideas are welcome. >> >> Reading this code again, even the addition case looks too aggressive to me. >> See: >> llvm.org/PR17452 - SCEV createNodeForPHI is too optimistic about NSW. >> > > If the behavior is different between 'add nsw' and 'sub nsw' then the SCEV > canonicalization of 'sub' leads to incorrect results. > > In your example both result should be the same but the ...

...e range of values that a variable can hold before the loop hits undefined behavior. I don’t know how to implement something like this yet. Ideas are welcome. >>> >>> Reading this code again, even the addition case looks too aggressive to me. >>> See: >>> llvm.org/PR17452 - SCEV createNodeForPHI is too optimistic about NSW. >>> >> >> If the behavior is different between 'add nsw' and 'sub nsw' then the SCEV >> canonicalization of 'sub' leads to incorrect results. > > Creating a SCEV expression for a sub instr...

...like to query the range of values that a > variable can hold before the loop hits undefined behavior. I don’t > know how to implement something like this yet. Ideas are welcome. > > Reading this code again, even the addition case looks too aggressive > to me. > See: > llvm.org/PR17452 - SCEV createNodeForPHI is too optimistic about NSW. > > -Andy > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev > -- Hal Finkel Assis...