[llvm-bugs] [Bug 43679] New: [LoopDataPrefetch] Creates prefetch 3.5 terabytes ahead

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=43679

            Bug ID: 43679
           Summary: [LoopDataPrefetch]  Creates prefetch 3.5 terabytes
                    ahead
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Loop Optimizer
          Assignee: unassignedbugs at nondot.org
          Reporter: paulsson at linux.vnet.ibm.com
                CC: llvm-bugs at lists.llvm.org

Created attachment 22671
  --> https://bugs.llvm.org/attachment.cgi?id=22671&action=edit
reduced testcase

NextLSCEV for the load in LoopDataPrefetch is
{(3564822854692 + @0),+,21474836474}<%bb6>

This seems to disappear if I revert 354ba69 "[CVP} Replace SExt with ZExt if
the input is known-non-negative".

bin/llc -mcpu=z13 -O1 -o - tc_loopdpf_oor.opt.ll

...
larl    %r1, __unnamed_1+3564822854692
...

This results in a linker error "relocation truncated to fit".

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