[llvm-dev] How to handle UMULO?

陳韋任 via llvm-dev llvm-dev at lists.llvm.org
Wed Feb 28 05:31:38 PST 2018

Hi All,

  While compiling libgcc, I find I have to deal with UMULO (overflow-aware
unsigned multiplication) SDNode. UMULO returns the result of
multiplication, and a boolean indicating overflow occurred or not. Our
target's multiply instruction doesn't care (detect) overflow. I am
wondering if I can always set the boolean to false. I am not sure about
this as I see AArch64 [1] seems trying to emulate the overflow behavior.




Wei-Ren Chen (陳韋任)
Homepage: https://people.cs.nctu.edu.tw/~chenwj
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