264 lines
		
	
	
		
			7.3 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			264 lines
		
	
	
		
			7.3 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; RUN: opt -verify-loop-info -irce -S < %s | FileCheck %s
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; RUN: opt -verify-loop-info -passes='require<branch-prob>,irce' -S < %s | FileCheck %s
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define void @decrementing_loop(i32 *%arr, i32 *%a_len_ptr, i32 %n) {
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 entry:
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  %len = load i32, i32* %a_len_ptr, !range !0
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  %first.itr.check = icmp sgt i32 %n, 0
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  %start = sub i32 %n, 1
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  br i1 %first.itr.check, label %loop, label %exit
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 loop:
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  %idx = phi i32 [ %start, %entry ] , [ %idx.dec, %in.bounds ]
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  %idx.dec = sub i32 %idx, 1
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  %abc.high = icmp slt i32 %idx, %len
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  %abc.low = icmp sge i32 %idx, 0
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  %abc = and i1 %abc.low, %abc.high
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  br i1 %abc, label %in.bounds, label %out.of.bounds, !prof !1
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 in.bounds:
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  %addr = getelementptr i32, i32* %arr, i32 %idx
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  store i32 0, i32* %addr
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  %next = icmp sgt i32 %idx.dec, -1
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  br i1 %next, label %loop, label %exit
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 out.of.bounds:
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  ret void
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 exit:
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  ret void
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; CHECK: loop.preheader:
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; CHECK:   [[len_hiclamp_cmp:[^ ]+]] = icmp slt i32 %len, %n
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; CHECK:   [[len_hiclamp:[^ ]+]] = select i1 [[len_hiclamp_cmp]], i32 %len, i32 %n
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; CHECK:   [[not_exit_preloop_at_cmp:[^ ]+]] = icmp sgt i32 [[len_hiclamp]], 0
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; CHECK:   [[not_exit_preloop_at:[^ ]+]] = select i1 [[not_exit_preloop_at_cmp]], i32 [[len_hiclamp]], i32 0
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; CHECK:   %exit.preloop.at = add nsw i32 [[not_exit_preloop_at]], -1
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}
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; Make sure that we can eliminate the range check when the loop looks like:
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; for (i = len.a - 1; i >= 0; --i)
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;   b[i] = a[i];
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define void @test_01(i32* %a, i32* %b, i32* %a_len_ptr, i32* %b_len_ptr) {
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; CHECK-LABEL: test_01
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; CHECK:       mainloop:
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; CHECK-NEXT:    br label %loop
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; CHECK:       loop:
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; CHECK:         %rc = and i1 true, true
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; CHECK:       loop.preloop:
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 entry:
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  %len.a = load i32, i32* %a_len_ptr, !range !0
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  %len.b = load i32, i32* %b_len_ptr, !range !0
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  %first.itr.check = icmp ne i32 %len.a, 0
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  br i1 %first.itr.check, label %loop, label %exit
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 loop:
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  %idx = phi i32 [ %len.a, %entry ] , [ %idx.next, %in.bounds ]
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  %idx.next = sub i32 %idx, 1
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  %rca = icmp ult i32 %idx.next, %len.a
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  %rcb = icmp ult i32 %idx.next, %len.b
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  %rc = and i1 %rca, %rcb
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  br i1 %rc, label %in.bounds, label %out.of.bounds, !prof !1
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 in.bounds:
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  %el.a = getelementptr i32, i32* %a, i32 %idx.next
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  %el.b = getelementptr i32, i32* %b, i32 %idx.next
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  %v = load i32, i32* %el.a
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  store i32 %v, i32* %el.b
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  %loop.cond = icmp slt i32 %idx, 2
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  br i1 %loop.cond, label %exit, label %loop
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 out.of.bounds:
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  ret void
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 exit:
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  ret void
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}
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; Same as test_01, but the latch condition is unsigned
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define void @test_02(i32* %a, i32* %b, i32* %a_len_ptr, i32* %b_len_ptr) {
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; CHECK-LABEL: test_02
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; CHECK:       mainloop:
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; CHECK-NEXT:    br label %loop
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; CHECK:       loop:
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; CHECK:         %rc = and i1 true, true
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; CHECK:       loop.preloop:
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 entry:
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  %len.a = load i32, i32* %a_len_ptr, !range !0
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  %len.b = load i32, i32* %b_len_ptr, !range !0
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  %first.itr.check = icmp ne i32 %len.a, 0
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  br i1 %first.itr.check, label %loop, label %exit
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 loop:
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  %idx = phi i32 [ %len.a, %entry ] , [ %idx.next, %in.bounds ]
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  %idx.next = sub i32 %idx, 1
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  %rca = icmp ult i32 %idx.next, %len.a
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  %rcb = icmp ult i32 %idx.next, %len.b
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  %rc = and i1 %rca, %rcb
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  br i1 %rc, label %in.bounds, label %out.of.bounds, !prof !1
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 in.bounds:
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  %el.a = getelementptr i32, i32* %a, i32 %idx.next
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  %el.b = getelementptr i32, i32* %b, i32 %idx.next
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  %v = load i32, i32* %el.a
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  store i32 %v, i32* %el.b
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  %loop.cond = icmp ult i32 %idx, 2
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  br i1 %loop.cond, label %exit, label %loop
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 out.of.bounds:
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  ret void
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 exit:
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  ret void
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}
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; Check that we can figure out that IV is non-negative via implication through
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; Phi node.
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define void @test_03(i32* %a, i32* %a_len_ptr, i1 %cond) {
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; CHECK-LABEL: test_03
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; CHECK:       mainloop:
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; CHECK-NEXT:    br label %loop
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; CHECK:       loop:
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; CHECK:         br i1 true, label %in.bounds, label %out.of.bounds
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; CHECK:       loop.preloop:
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 entry:
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  %len.a = load i32, i32* %a_len_ptr, !range !0
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  %len.minus.one = sub nsw i32 %len.a, 1
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  %len.minus.two = sub nsw i32 %len.a, 2
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  br i1 %cond, label %if.true, label %if.false
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if.true:
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  br label %merge
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if.false:
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  br label %merge
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merge:
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  %starting.value = phi i32 [ %len.minus.two, %if.true ], [ %len.minus.one, %if.false ]
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  %first.itr.check = icmp sgt i32 %len.a, 3
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  br i1 %first.itr.check, label %loop, label %exit
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loop:
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  %idx = phi i32 [ %starting.value, %merge ] , [ %idx.next, %in.bounds ]
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  %idx.next = sub i32 %idx, 1
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  %rc = icmp ult i32 %idx.next, %len.a
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  br i1 %rc, label %in.bounds, label %out.of.bounds, !prof !1
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in.bounds:
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  %el.a = getelementptr i32, i32* %a, i32 %idx.next
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  %v = load i32, i32* %el.a
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  %loop.cond = icmp slt i32 %idx, 2
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  br i1 %loop.cond, label %exit, label %loop
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out.of.bounds:
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  ret void
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exit:
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  ret void
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}
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; Check that we can figure out that IV is non-negative via implication through
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; two Phi nodes.
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define void @test_04(i32* %a, i32* %a_len_ptr, i1 %cond) {
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; CHECK-LABEL: test_04
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; CHECK:       mainloop:
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; CHECK-NEXT:    br label %loop
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; CHECK:       loop:
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; CHECK:         br i1 true, label %in.bounds, label %out.of.bounds
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; CHECK:       loop.preloop:
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 entry:
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  %len.a = load i32, i32* %a_len_ptr, !range !0
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  %len.minus.one = sub nsw i32 %len.a, 1
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  %len.plus.one = add nsw i32 %len.a, 1
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  %len.minus.two = sub nsw i32 %len.a, 2
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  br i1 %cond, label %if.true, label %if.false
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if.true:
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  br label %merge
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if.false:
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  br label %merge
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merge:
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  %starting.value = phi i32 [ %len.minus.two, %if.true ], [ %len.minus.one, %if.false ]
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  %len.phi = phi i32 [ %len.a, %if.true ], [ %len.plus.one, %if.false ]
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  %first.itr.check = icmp sgt i32 %len.a, 3
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  br i1 %first.itr.check, label %loop, label %exit
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loop:
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  %idx = phi i32 [ %starting.value, %merge ] , [ %idx.next, %in.bounds ]
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  %idx.next = sub i32 %idx, 1
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  %rc = icmp ult i32 %idx.next, %len.phi
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  br i1 %rc, label %in.bounds, label %out.of.bounds, !prof !1
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in.bounds:
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  %el.a = getelementptr i32, i32* %a, i32 %idx.next
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  %v = load i32, i32* %el.a
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  %loop.cond = icmp slt i32 %idx, 2
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  br i1 %loop.cond, label %exit, label %loop
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out.of.bounds:
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  ret void
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exit:
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  ret void
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}
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; Check that we can figure out that IV is non-negative via implication through
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; two Phi nodes, one being AddRec.
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define void @test_05(i32* %a, i32* %a_len_ptr, i1 %cond) {
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; CHECK-LABEL: test_05
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; CHECK:       mainloop:
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; CHECK-NEXT:    br label %loop
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; CHECK:       loop:
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; CHECK:         br i1 true, label %in.bounds, label %out.of.bounds
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; CHECK:       loop.preloop:
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 entry:
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  %len.a = load i32, i32* %a_len_ptr, !range !0
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  %len.minus.one = sub nsw i32 %len.a, 1
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  %len.plus.one = add nsw i32 %len.a, 1
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  %len.minus.two = sub nsw i32 %len.a, 2
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  br label %merge
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merge:
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  %starting.value = phi i32 [ %len.minus.two, %entry ], [ %len.minus.one, %merge ]
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  %len.phi = phi i32 [ %len.a, %entry ], [ %len.phi.next, %merge ]
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  %len.phi.next = add nsw i32 %len.phi, 1
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  br i1 true, label %first.iter.check, label %merge
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first.iter.check:
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  %first.itr.check = icmp sgt i32 %len.a, 3
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  br i1 %first.itr.check, label %loop, label %exit
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loop:
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  %idx = phi i32 [ %starting.value, %first.iter.check ] , [ %idx.next, %in.bounds ]
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  %idx.next = sub i32 %idx, 1
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  %rc = icmp ult i32 %idx.next, %len.phi
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  br i1 %rc, label %in.bounds, label %out.of.bounds, !prof !1
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in.bounds:
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  %el.a = getelementptr i32, i32* %a, i32 %idx.next
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  %v = load i32, i32* %el.a
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  %loop.cond = icmp slt i32 %idx, 2
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  br i1 %loop.cond, label %exit, label %loop
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out.of.bounds:
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  ret void
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exit:
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  ret void
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}
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!0 = !{i32 0, i32 2147483647}
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!1 = !{!"branch_weights", i32 64, i32 4}
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