[llvm-bugs] [Bug 38674] New: 'Assertion `L->isRecursivelyLCSSAForm(*DT, *LI) && "Indvars did not preserve LCSSA!"' failed.' with -indvars

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=38674

            Bug ID: 38674
           Summary: 'Assertion `L->isRecursivelyLCSSAForm(*DT, *LI) &&
                    "Indvars did not preserve LCSSA!"' failed.' with
                    -indvars
           Product: new-bugs
           Version: unspecified
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: new bugs
          Assignee: unassignedbugs at nondot.org
          Reporter: mikael.holmen at ericsson.com
                CC: llvm-bugs at lists.llvm.org

Created attachment 20758
  --> https://bugs.llvm.org/attachment.cgi?id=20758&action=edit
reproducer

opt -S -o - bbi-16913.ll -indvars

crashes with

opt: ../lib/Transforms/Scalar/IndVarSimplify.cpp:2519: bool (anonymous
namespace)::IndVarSimplify::run(llvm::Loop *): Assertion
`L->isRecursivelyLCSSAForm(*DT, *LI) && "Indvars did not preserve LCSSA!"'
failed.

The function looks like this when the assertion fails

define i32 @f1() {
entry:
   br label %for.cond1.preheader

for.cond1.preheader:                              ; preds = %for.end9, 
%entry
   br label %for.cond4.preheader

for.cond4.preheader:                              ; preds = %for.end, 
%for.cond1.preheader
   %zext = zext i16 1 to i32
   br label %for.body6

for.cond4:                                        ; preds = %for.body6
   %cmp5 = icmp ult i32 %inc, 2
   br i1 %cmp5, label %for.body6, label %for.end

for.body6:                                        ; preds = %for.cond4, 
%for.cond4.preheader
   %storemerge26 = phi i32 [ 0, %for.cond4.preheader ], [ %inc, %for.cond4 ]
   %0 = icmp eq i32 %storemerge26, %zext
   %inc = add nuw nsw i32 %storemerge26, 1
   br i1 %0, label %return.loopexit, label %for.cond4

for.end:                                          ; preds = %for.cond4
   br i1 false, label %for.cond4.preheader, label %for.end9

for.end9:                                         ; preds = %for.end
   br i1 false, label %for.cond1.preheader, label %return.loopexit3

return.loopexit:                                  ; preds = %for.body6
   unreachable

return.loopexit3:                                 ; preds = %for.end9
   %inc11.lcssa = phi i32 [ %zext, %for.end9 ]
   br label %return

return:                                           ; preds = 
%return.loopexit3
   ret i32 %inc11.lcssa
}

This started happening with r335020.

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20180823/0a0fd32f/attachment-0001.html>