355 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			355 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			LLVM
		
	
	
	
| ; RUN: opt -loop-vectorize -force-vector-width=2 -S < %s 2>&1 | FileCheck %s
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| ; RUN: opt -indvars -S < %s 2>&1 | FileCheck %s -check-prefix=INDVARCHECK
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| 
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| target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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| target triple = "x86_64-unknown-linux-gnu"
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| 
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| ; Produced from test-case:
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| ;
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| ; void testCountIncrLoop(unsigned char *ptr, int lim, int count, int val)
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| ; {
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| ;   int inx = 0;
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| ;   for (int outer_i = 0; outer_i < lim; ++outer_i) {
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| ;     if (count > 0) { // At runtime, 'count' is 0, so the following code is dead.
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| ;       int result = val;
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| ;       int tmp = count;
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| ;
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| ;       while (tmp < 8) {
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| ;         result += val >> tmp;
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| ;         tmp += count;
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| ;       }
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| ;
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| ;       ptr[inx++] = (unsigned char) result;
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| ;     }
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| ;   }
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| ; }
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| ;
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| ; No explicit division appears in the input, but a division is generated during
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| ; vectorization, and that division is a division-by-0 when the input 'count'
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| ; is 0, so it cannot be hoisted above the guard of 'count > 0'.
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| 
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| ; Verify that a 'udiv' does not appear in the 'loop1.preheader' block, and that
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| ; a 'udiv' has been inserted at the top of the 'while.body.preheader' block.
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| define void @testCountIncrLoop(i8* %ptr, i32 %lim, i32 %count, i32 %val) {
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| ; CHECK-LABEL: @testCountIncrLoop(
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| ; CHECK-NEXT:  entry:
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| ; CHECK:       loop1.preheader:
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| ; CHECK-NOT:     udiv
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| ; CHECK:       loop1.body:
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| ; CHECK:       while.cond.preheader:
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| ; CHECK:       while.body.preheader:
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| ; CHECK-NEXT:    [[TMP1:%.*]] = udiv i32 [[TMP0:%.*]], [[COUNT:%.*]]
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| ; CHECK:       vector.ph:
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| ; CHECK:       exit:
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| ; CHECK:         ret void
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| ;
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| entry:
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|   %cmp1 = icmp sgt i32 %lim, 0
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|   br i1 %cmp1, label %loop1.preheader, label %exit
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| 
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| loop1.preheader:                                  ; preds = %entry
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|   %cmp2 = icmp sgt i32 %count, 0
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|   %cmp4 = icmp slt i32 %count, 8
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|   br label %loop1.body
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| 
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| loop1.body:                                       ; preds = %loop1.inc, %loop1.preheader
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|   %outer_i = phi i32 [ 0, %loop1.preheader ], [ %outer_i.1, %loop1.inc ]
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|   %inx.1 = phi i32 [ 0, %loop1.preheader ], [ %inx.2, %loop1.inc ]
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|   br i1 %cmp2, label %while.cond.preheader, label %loop1.inc
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| 
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| while.cond.preheader:                             ; preds = %loop1.body
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|   br i1 %cmp4, label %while.body, label %while.end
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| 
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| while.body:                                       ; preds = %while.body, %while.cond.preheader
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|   %tmp = phi i32 [ %add3, %while.body ], [ %count, %while.cond.preheader ]
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|   %result.1 = phi i32 [ %add, %while.body ], [ %val, %while.cond.preheader ]
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|   %shr = ashr i32 %val, %tmp
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|   %add = add nsw i32 %shr, %result.1
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|   %add3 = add nsw i32 %tmp, %count
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|   %cmp3 = icmp slt i32 %add3, 8
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|   br i1 %cmp3, label %while.body, label %while.end
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| 
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| while.end:                                        ; preds = %while.body, %while.cond.preheader
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|   %result.0.lcssa = phi i32 [ %val, %while.cond.preheader ], [ %add, %while.body ]
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|   %conv = trunc i32 %result.0.lcssa to i8
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|   %inc = add nsw i32 %inx.1, 1
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|   %idxprom = sext i32 %inx.1 to i64
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|   %arrayidx = getelementptr inbounds i8, i8* %ptr, i64 %idxprom
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|   store i8 %conv, i8* %arrayidx, align 1
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|   br label %loop1.inc
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| 
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| loop1.inc:                                        ; preds = %while.end, %loop1.body
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|   %inx.2 = phi i32 [ %inc, %while.end ], [ %inx.1, %loop1.body ]
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|   %outer_i.1 = add nuw nsw i32 %outer_i, 1
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|   %exitcond = icmp eq i32 %outer_i.1, %lim
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|   br i1 %exitcond, label %exit, label %loop1.body
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| 
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| exit:                                             ; preds = %loop1.inc, %entry
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|   ret void
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| }
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| 
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| ; These next tests are all based on the following source code, with slight
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| ; variations on the calculation of 'incr' (all of which are loop-invariant
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| ; divisions, but only some of which can be safely hoisted):
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| ;
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| ; uint32_t foo(uint32_t *ptr, uint32_t start1, uint32_t start2) {
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| ;   uint32_t counter1, counter2;
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| ;   uint32_t val = start1;
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| ;   for (counter1 = 1; counter1 < 100; ++counter1) {
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| ;     uint32_t index = 0;
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| ;     val += ptr[index];
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| ;     for (counter2 = start2; counter2 < 10; ++counter2) {
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| ;       // Division is loop invariant, and denominator is guaranteed non-zero:
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| ;       // Safe to hoist it out of the inner loop.
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| ;       uint32_t incr = 16 / counter1;
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| ;       index += incr;
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| ;       val += ptr[index];
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| ;     }
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| ;   }
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| ;   return val;
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| ; }
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| 
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| ; This version is as written above, where 'incr' is '16/counter1', and it is
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| ; guaranted that 'counter1' is always non-zero.  So it is safe to hoist the
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| ; division from the inner loop to the preheader.
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| ;
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| ; Verify that the 'udiv' is hoisted to the preheader, and is not in the loop body.
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| define i32 @NonZeroDivHoist(i32* nocapture readonly %ptr, i32 %start1, i32 %start2) {
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| ; INDVARCHECK-LABEL: @NonZeroDivHoist(
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| ; INDVARCHECK-NEXT:  entry:
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| ; INDVARCHECK:       for.body3.lr.ph:
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| ; INDVARCHECK-NEXT:    [[TMP0:%.*]] = udiv i64 16, [[INDVARS_IV:%.*]]
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| ; INDVARCHECK-NEXT:    br label [[FOR_BODY3:%.*]]
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| ; INDVARCHECK:       for.body3:
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| ; INDVARCHECK-NOT:     udiv
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| ; INDVARCHECK:       for.end10:
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| ;
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| entry:
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|   br label %for.cond
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| 
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| for.cond:                                         ; preds = %for.end, %entry
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|   %val.0 = phi i32 [ %start1, %entry ], [ %val.1.lcssa, %for.end ]
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|   %counter1.0 = phi i32 [ 1, %entry ], [ %inc9, %for.end ]
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|   %cmp = icmp ult i32 %counter1.0, 100
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|   br i1 %cmp, label %for.body, label %for.end10
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| 
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| for.body:                                         ; preds = %for.cond
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|   %tmp = load i32, i32* %ptr, align 4
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|   %add = add i32 %tmp, %val.0
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|   %cmp224 = icmp ult i32 %start2, 10
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|   br i1 %cmp224, label %for.body3.lr.ph, label %for.end
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| 
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| for.body3.lr.ph:                                  ; preds = %for.body
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|   br label %for.body3
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| 
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| for.body3:                                        ; preds = %for.body3, %for.body3.lr.ph
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|   %index.027 = phi i32 [ 0, %for.body3.lr.ph ], [ %add4, %for.body3 ]
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|   %val.126 = phi i32 [ %add, %for.body3.lr.ph ], [ %add7, %for.body3 ]
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|   %counter2.025 = phi i32 [ %start2, %for.body3.lr.ph ], [ %inc, %for.body3 ]
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|   %div = udiv i32 16, %counter1.0
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|   %add4 = add i32 %div, %index.027
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|   %idxprom5 = zext i32 %add4 to i64
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|   %arrayidx6 = getelementptr inbounds i32, i32* %ptr, i64 %idxprom5
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|   %tmp1 = load i32, i32* %arrayidx6, align 4
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|   %add7 = add i32 %tmp1, %val.126
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|   %inc = add i32 %counter2.025, 1
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|   %cmp2 = icmp ult i32 %inc, 10
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|   br i1 %cmp2, label %for.body3, label %for.cond1.for.end_crit_edge
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| 
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| for.cond1.for.end_crit_edge:                      ; preds = %for.body3
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|   %split = phi i32 [ %add7, %for.body3 ]
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|   br label %for.end
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| 
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| for.end:                                          ; preds = %for.cond1.for.end_crit_edge, %for.body
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|   %val.1.lcssa = phi i32 [ %split, %for.cond1.for.end_crit_edge ], [ %add, %for.body ]
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|   %inc9 = add i32 %counter1.0, 1
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|   br label %for.cond
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| 
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| for.end10:                                        ; preds = %for.cond
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|   %val.0.lcssa = phi i32 [ %val.0, %for.cond ]
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|   ret i32 %val.0.lcssa
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| }
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| 
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| ; This version is identical to the above 'NonZeroDivHoist' case, except the
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| ; outer ('counter1') loop starts at the unknown value of 'start1' rather than 1,
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| ; and so it is illegal to hoist the division because if 'start1' is 0, hoisting
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| ; it would incorrectly cause a divide-by-zero trap.
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| ;
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| ; Verify that the 'udiv' is not hoisted to the preheader, and it remains in the
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| ; loop body.
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| define i32 @ZeroDivNoHoist(i32* nocapture readonly %ptr, i32 %start1, i32 %start2) {
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| ; INDVARCHECK-LABEL: @ZeroDivNoHoist(
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| ; INDVARCHECK-NEXT:  entry:
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| ; INDVARCHECK-NOT:     udiv
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| ; INDVARCHECK:       for.body3:
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| ; INDVARCHECK:         [[TMP1:%.*]] = udiv i64 16, [[INDVARS_IV:%.*]]
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| ; INDVARCHECK:       for.cond1.for.end_crit_edge:
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| ;
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| entry:
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|   br label %for.cond
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| 
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| for.cond:                                         ; preds = %for.end, %entry
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|   %val.0 = phi i32 [ %start1, %entry ], [ %val.1.lcssa, %for.end ]
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|   %counter1.0 = phi i32 [ %start1, %entry ], [ %inc9, %for.end ]
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|   %cmp = icmp ult i32 %counter1.0, 100
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|   br i1 %cmp, label %for.body, label %for.end10
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| 
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| for.body:                                         ; preds = %for.cond
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|   %tmp = load i32, i32* %ptr, align 4
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|   %add = add i32 %tmp, %val.0
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|   %cmp224 = icmp ult i32 %start2, 10
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|   br i1 %cmp224, label %for.body3.lr.ph, label %for.end
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| 
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| for.body3.lr.ph:                                  ; preds = %for.body
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|   br label %for.body3
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| 
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| for.body3:                                        ; preds = %for.body3, %for.body3.lr.ph
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|   %index.027 = phi i32 [ 0, %for.body3.lr.ph ], [ %add4, %for.body3 ]
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|   %val.126 = phi i32 [ %add, %for.body3.lr.ph ], [ %add7, %for.body3 ]
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|   %counter2.025 = phi i32 [ %start2, %for.body3.lr.ph ], [ %inc, %for.body3 ]
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|   %div = udiv i32 16, %counter1.0
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|   %add4 = add i32 %div, %index.027
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|   %idxprom5 = zext i32 %add4 to i64
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|   %arrayidx6 = getelementptr inbounds i32, i32* %ptr, i64 %idxprom5
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|   %tmp1 = load i32, i32* %arrayidx6, align 4
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|   %add7 = add i32 %tmp1, %val.126
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|   %inc = add i32 %counter2.025, 1
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|   %cmp2 = icmp ult i32 %inc, 10
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|   br i1 %cmp2, label %for.body3, label %for.cond1.for.end_crit_edge
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| 
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| for.cond1.for.end_crit_edge:                      ; preds = %for.body3
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|   %split = phi i32 [ %add7, %for.body3 ]
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|   br label %for.end
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| 
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| for.end:                                          ; preds = %for.cond1.for.end_crit_edge, %for.body
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|   %val.1.lcssa = phi i32 [ %split, %for.cond1.for.end_crit_edge ], [ %add, %for.body ]
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|   %inc9 = add i32 %counter1.0, 1
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|   br label %for.cond
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| 
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| for.end10:                                        ; preds = %for.cond
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|   %val.0.lcssa = phi i32 [ %val.0, %for.cond ]
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|   ret i32 %val.0.lcssa
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| }
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| 
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| ; This version is has a clearly safe division by a non-zero constant (16).  The
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| ; division is transformed to a logical-shift-right of 4, and it is safely
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| ; hoisted.
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| ;
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| ; Verify that the division-operation is hoisted, and that it appears as a
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| ; right-shift ('lshr') rather than an explicit division.
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| define i32 @DivBy16Hoist(i32* nocapture readonly %ptr, i32 %start1, i32 %start2) {
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| ; INDVARCHECK-LABEL: @DivBy16Hoist(
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| ; INDVARCHECK-NEXT:  entry:
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| ; INDVARCHECK:       for.cond:
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| ; INDVARCHECK:         [[TMP1:%.*]] = lshr i64 [[INDVARS_IV:%.*]], 4
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| ; INDVARCHECK:       for.body:
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| ; INDVARCHECK-NOT:     lshr
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| ; INDVARCHECK-NOT:     udiv
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| ; INDVARCHECK:       for.end10:
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| ;
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| entry:
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|   br label %for.cond
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| 
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| for.cond:                                         ; preds = %for.end, %entry
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|   %val.0 = phi i32 [ %start1, %entry ], [ %val.1.lcssa, %for.end ]
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|   %counter1.0 = phi i32 [ %start1, %entry ], [ %inc9, %for.end ]
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|   %cmp = icmp ult i32 %counter1.0, 100
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|   br i1 %cmp, label %for.body, label %for.end10
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| 
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| for.body:                                         ; preds = %for.cond
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|   %tmp = load i32, i32* %ptr, align 4
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|   %add = add i32 %tmp, %val.0
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|   %cmp224 = icmp ult i32 %start2, 10
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|   br i1 %cmp224, label %for.body3.lr.ph, label %for.end
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| 
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| for.body3.lr.ph:                                  ; preds = %for.body
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|   br label %for.body3
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| 
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| for.body3:                                        ; preds = %for.body3, %for.body3.lr.ph
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|   %index.027 = phi i32 [ 0, %for.body3.lr.ph ], [ %add4, %for.body3 ]
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|   %val.126 = phi i32 [ %add, %for.body3.lr.ph ], [ %add7, %for.body3 ]
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|   %counter2.025 = phi i32 [ %start2, %for.body3.lr.ph ], [ %inc, %for.body3 ]
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|   %div = udiv i32 %counter1.0, 16
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|   %add4 = add i32 %div, %index.027
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|   %idxprom5 = zext i32 %add4 to i64
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|   %arrayidx6 = getelementptr inbounds i32, i32* %ptr, i64 %idxprom5
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|   %tmp1 = load i32, i32* %arrayidx6, align 4
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|   %add7 = add i32 %tmp1, %val.126
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|   %inc = add i32 %counter2.025, 1
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|   %cmp2 = icmp ult i32 %inc, 10
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|   br i1 %cmp2, label %for.body3, label %for.cond1.for.end_crit_edge
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| 
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| for.cond1.for.end_crit_edge:                      ; preds = %for.body3
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|   %split = phi i32 [ %add7, %for.body3 ]
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|   br label %for.end
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| 
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| for.end:                                          ; preds = %for.cond1.for.end_crit_edge, %for.body
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|   %val.1.lcssa = phi i32 [ %split, %for.cond1.for.end_crit_edge ], [ %add, %for.body ]
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|   %inc9 = add i32 %counter1.0, 1
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|   br label %for.cond
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| 
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| for.end10:                                        ; preds = %for.cond
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|   %val.0.lcssa = phi i32 [ %val.0, %for.cond ]
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|   ret i32 %val.0.lcssa
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| }
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| 
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| ; This version is has a clearly safe division by a non-zero constant (17).  The
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| ; division is safely hoisted, as it was in the 'DivBy16Hoist' verison, but here
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| ; it remains a division, rather than being transformed to a right-shift.
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| ;
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| ; Verify that the division-operation is hoisted.
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| define i32 @DivBy17Hoist(i32* nocapture readonly %ptr, i32 %start1, i32 %start2) {
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| ; INDVARCHECK-LABEL: @DivBy17Hoist(
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| ; INDVARCHECK-NEXT:  entry:
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| ; INDVARCHECK:       for.cond:
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| ; INDVARCHECK:         [[TMP1:%.*]] = udiv i64 [[INDVARS_IV:%.*]], 17
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| ; INDVARCHECK:       for.body:
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| ; INDVARCHECK-NOT:     udiv
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| ; INDVARCHECK:       for.end10:
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| ;
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| entry:
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|   br label %for.cond
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| 
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| for.cond:                                         ; preds = %for.end, %entry
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|   %val.0 = phi i32 [ %start1, %entry ], [ %val.1.lcssa, %for.end ]
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|   %counter1.0 = phi i32 [ %start1, %entry ], [ %inc9, %for.end ]
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|   %cmp = icmp ult i32 %counter1.0, 100
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|   br i1 %cmp, label %for.body, label %for.end10
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| 
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| for.body:                                         ; preds = %for.cond
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|   %tmp = load i32, i32* %ptr, align 4
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|   %add = add i32 %tmp, %val.0
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|   %cmp224 = icmp ult i32 %start2, 10
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|   br i1 %cmp224, label %for.body3.lr.ph, label %for.end
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| 
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| for.body3.lr.ph:                                  ; preds = %for.body
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|   br label %for.body3
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| 
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| for.body3:                                        ; preds = %for.body3, %for.body3.lr.ph
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|   %index.027 = phi i32 [ 0, %for.body3.lr.ph ], [ %add4, %for.body3 ]
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|   %val.126 = phi i32 [ %add, %for.body3.lr.ph ], [ %add7, %for.body3 ]
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|   %counter2.025 = phi i32 [ %start2, %for.body3.lr.ph ], [ %inc, %for.body3 ]
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|   %div = udiv i32 %counter1.0, 17
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|   %add4 = add i32 %div, %index.027
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|   %idxprom5 = zext i32 %add4 to i64
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|   %arrayidx6 = getelementptr inbounds i32, i32* %ptr, i64 %idxprom5
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|   %tmp1 = load i32, i32* %arrayidx6, align 4
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|   %add7 = add i32 %tmp1, %val.126
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|   %inc = add i32 %counter2.025, 1
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|   %cmp2 = icmp ult i32 %inc, 10
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|   br i1 %cmp2, label %for.body3, label %for.cond1.for.end_crit_edge
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| 
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| for.cond1.for.end_crit_edge:                      ; preds = %for.body3
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|   %split = phi i32 [ %add7, %for.body3 ]
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|   br label %for.end
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| 
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| for.end:                                          ; preds = %for.cond1.for.end_crit_edge, %for.body
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|   %val.1.lcssa = phi i32 [ %split, %for.cond1.for.end_crit_edge ], [ %add, %for.body ]
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|   %inc9 = add i32 %counter1.0, 1
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|   br label %for.cond
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| 
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| for.end10:                                        ; preds = %for.cond
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|   %val.0.lcssa = phi i32 [ %val.0, %for.cond ]
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|   ret i32 %val.0.lcssa
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| }
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