[LLVMdev] regarding opt -indvars

[Edvard Ghazaryan]

Hello .

I ran opt with -indvars options , got wrong result. 
This is my example:
test.cc : 
int test(int a)
                {
     for (int i = 2; i < a; ++i) {
                           a += ;
     }
             return a;
}
clang -O3 -emit-llvm -S test.cc -o test.ll
opt -indvards -S test.ll  -o indvars.ll > /dev/null

indvars.ll :

; ModuleID = 'test.ll'
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32-S128"
target triple = "i386-pc-linux-gnu"

define i32 @_Z4testi(i32 %a) nounwind readnone {
entry:
  %cmp1 = icmp sgt i32 %a, 2
  br i1 %cmp1, label %for.body.preheader, label %for.end

for.body.preheader:                               ; preds = %entry
  br label %for.body

for.body:                                         ; preds = %for.body.preheader, %for.body
  %a.addr.03 = phi i32 [ %add, %for.body ], [ %a, %for.body.preheader ]  //should start at 0 , I think there is no Canonicalize Induction Variable
  %i.02 = phi i32 [ %inc, %for.body ], [ 2, %for.body.preheader ]
  %add = add nsw i32 %a.addr.03, %i.02
  %inc = add nsw i32 %i.02, 1
  %cmp = icmp slt i32 %inc, %add
  br i1 %cmp, label %for.body, label %for.end.loopexit

for.end.loopexit:                                 ; preds = %for.body
  %add.lcssa = phi i32 [ %add, %for.body ]
  br label %for.end

for.end:                                          ; preds = %for.end.loopexit, %entry
  %a.addr.0.lcssa = phi i32 [ %a, %entry ], [ %add.lcssa, %for.end.loopexit ]
  ret i32 %a.addr.0.lcssa
}

Someone can explain why?

Thanks in advance,
Edvard 
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