[llvm-dev] Regarding Dependence distance dump (original) (raw)

Venkataramanan Kumar via llvm-dev llvm-dev at lists.llvm.org
Tue Sep 18 06:30:19 PDT 2018

Hi,

For the below test case, I need the dependence distance between the array references "a[j][i]" and "a[j-1][i-2]".

--Snip-- int a[5][5]; int b[10];

void test() { for (int j=1;j<5;j++) for (int i=2;i<5;i++) { a[j][i] = 3.0; b[i]= a[j-1][i-2] ; } } --Snip-

Compile steps clang -O1 -emit-llvm -S test.c opt -analyze -da dist.ll

I tried dumping the dependence information with LLVM trunk (2018_09_17), it shows:

Printing analysis 'Dependence Analysis' for function 'test': da analyze - none! da analyze - flow [< <>]! <== dumps direction vector da analyze - none! da analyze - none! da analyze - none! da analyze - consistent output [S 0]!

LLVM Release 6.0.1 dumps the expected distance. Printing analysis 'Dependence Analysis' for function 'test': da analyze - none! da analyze - consistent flow [1 2]! da analyze - none! da analyze - none! da analyze - none! da analyze - consistent output [S 0]!

In trunk, it is now showing directions instead of distances. How to get the dependence distance?

regards, Venkat. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20180918/8ec02f89/attachment.html>

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