225 lines
		
	
	
		
			6.5 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			225 lines
		
	
	
		
			6.5 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; RUN: opt < %s -tailcallelim -verify-dom-info -S | FileCheck %s
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; RUN: opt < %s -passes=tailcallelim -verify-dom-info -S | FileCheck %s
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define i32 @test1_factorial(i32 %x) {
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entry:
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	%tmp.1 = icmp sgt i32 %x, 0
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	br i1 %tmp.1, label %then, label %else
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then:
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	%tmp.6 = add i32 %x, -1
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	%recurse = call i32 @test1_factorial( i32 %tmp.6 )
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	%accumulate = mul i32 %recurse, %x
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	ret i32 %accumulate
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else:
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	ret i32 1
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}
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; CHECK-LABEL: define i32 @test1_factorial(
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; CHECK: tailrecurse:
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; CHECK: %accumulator.tr = phi i32 [ 1, %entry ], [ %accumulate, %then ]
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; CHECK: then:
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; CHECK-NOT: %recurse
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; CHECK: %accumulate = mul i32 %accumulator.tr, %x.tr
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; CHECK: else:
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; CHECK: %accumulator.ret.tr = mul i32 %accumulator.tr, 1
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; CHECK: ret i32 %accumulator.ret.tr
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; This is a more aggressive form of accumulator recursion insertion, which 
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; requires noticing that X doesn't change as we perform the tailcall.
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define i32 @test2_mul(i32 %x, i32 %y) {
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entry:
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	%tmp.1 = icmp eq i32 %y, 0
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	br i1 %tmp.1, label %return, label %endif
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endif:
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	%tmp.8 = add i32 %y, -1
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	%recurse = call i32 @test2_mul( i32 %x, i32 %tmp.8 )
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	%accumulate = add i32 %recurse, %x
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	ret i32 %accumulate
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return:
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	ret i32 %x
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}
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; CHECK-LABEL: define i32 @test2_mul(
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; CHECK: tailrecurse:
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; CHECK: %accumulator.tr = phi i32 [ 0, %entry ], [ %accumulate, %endif ]
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; CHECK: endif:
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; CHECK-NOT: %recurse
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; CHECK: %accumulate = add i32 %accumulator.tr, %x
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; CHECK: return:
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; CHECK: %accumulator.ret.tr = add i32 %accumulator.tr, %x
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; CHECK: ret i32 %accumulator.ret.tr
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define i64 @test3_fib(i64 %n) nounwind readnone {
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entry:
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  switch i64 %n, label %bb1 [
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    i64 0, label %bb2
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    i64 1, label %bb2
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  ]
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bb1:
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  %0 = add i64 %n, -1
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  %recurse1 = tail call i64 @test3_fib(i64 %0) nounwind
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  %1 = add i64 %n, -2
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  %recurse2 = tail call i64 @test3_fib(i64 %1) nounwind
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  %accumulate = add nsw i64 %recurse2, %recurse1
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  ret i64 %accumulate
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bb2:
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  ret i64 %n
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}
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; CHECK-LABEL: define i64 @test3_fib(
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; CHECK: tailrecurse:
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; CHECK: %accumulator.tr = phi i64 [ 0, %entry ], [ %accumulate, %bb1 ]
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; CHECK: bb1:
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; CHECK-NOT: %recurse2
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; CHECK: %accumulate = add nsw i64 %accumulator.tr, %recurse1
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; CHECK: bb2:
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; CHECK: %accumulator.ret.tr = add nsw i64 %accumulator.tr, %n.tr
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; CHECK: ret i64 %accumulator.ret.tr
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define i32 @test4_base_case_call() local_unnamed_addr {
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entry:
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  %base = call i32 @test4_helper()
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  switch i32 %base, label %sw.default [
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    i32 1, label %cleanup
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    i32 5, label %cleanup
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    i32 7, label %cleanup
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  ]
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sw.default:
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  %recurse = call i32 @test4_base_case_call()
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  %accumulate = add nsw i32 %recurse, 1
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  br label %cleanup
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cleanup:
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  %retval.0 = phi i32 [ %accumulate, %sw.default ], [ %base, %entry ], [ %base, %entry ], [ %base, %entry ]
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  ret i32 %retval.0
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}
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declare i32 @test4_helper()
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; CHECK-LABEL: define i32 @test4_base_case_call(
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; CHECK: tailrecurse:
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; CHECK: %accumulator.tr = phi i32 [ 0, %entry ], [ %accumulate, %sw.default ]
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; CHECK: sw.default:
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; CHECK-NOT: %recurse
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; CHECK: %accumulate = add nsw i32 %accumulator.tr, 1
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; CHECK: cleanup:
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; CHECK: %accumulator.ret.tr = add nsw i32 %accumulator.tr, %base
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; CHECK: ret i32 %accumulator.ret.tr
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define i32 @test5_base_case_load(i32* nocapture %A, i32 %n) local_unnamed_addr {
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entry:
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  %cmp = icmp eq i32 %n, 0
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  br i1 %cmp, label %if.then, label %if.end
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if.then:
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  %base = load i32, i32* %A, align 4
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  ret i32 %base
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if.end:
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  %idxprom = zext i32 %n to i64
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  %arrayidx1 = getelementptr inbounds i32, i32* %A, i64 %idxprom
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  %load = load i32, i32* %arrayidx1, align 4
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  %sub = add i32 %n, -1
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  %recurse = tail call i32 @test5_base_case_load(i32* %A, i32 %sub)
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  %accumulate = add i32 %recurse, %load
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  ret i32 %accumulate
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}
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; CHECK-LABEL: define i32 @test5_base_case_load(
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; CHECK: tailrecurse:
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; CHECK: %accumulator.tr = phi i32 [ 0, %entry ], [ %accumulate, %if.end ]
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; CHECK: if.then:
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; CHECK: %accumulator.ret.tr = add i32 %accumulator.tr, %base
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; CHECK: ret i32 %accumulator.ret.tr
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; CHECK: if.end:
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; CHECK-NOT: %recurse
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; CHECK: %accumulate = add i32 %accumulator.tr, %load
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define i32 @test6_multiple_returns(i32 %x, i32 %y) local_unnamed_addr {
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entry:
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  switch i32 %x, label %default [
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    i32 0, label %case0
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    i32 99, label %case99
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  ]
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case0:
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  %helper = call i32 @test6_helper()
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  ret i32 %helper
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case99:
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  %sub1 = add i32 %x, -1
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  %recurse1 = call i32 @test6_multiple_returns(i32 %sub1, i32 %y)
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  ret i32 18
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default:
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  %sub2 = add i32 %x, -1
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  %recurse2 = call i32 @test6_multiple_returns(i32 %sub2, i32 %y)
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  %accumulate = add i32 %recurse2, %y
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  ret i32 %accumulate
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}
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declare i32 @test6_helper()
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; CHECK-LABEL: define i32 @test6_multiple_returns(
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; CHECK: tailrecurse:
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; CHECK: %accumulator.tr = phi i32 [ %accumulator.tr, %case99 ], [ 0, %entry ], [ %accumulate, %default ]
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; CHECK: %ret.tr = phi i32 [ undef, %entry ], [ %current.ret.tr, %case99 ], [ %ret.tr, %default ]
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; CHECK: %ret.known.tr = phi i1 [ false, %entry ], [ true, %case99 ], [ %ret.known.tr, %default ]
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; CHECK: case0:
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; CHECK: %accumulator.ret.tr2 = add i32 %accumulator.tr, %helper
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; CHECK: %current.ret.tr1 = select i1 %ret.known.tr, i32 %ret.tr, i32 %accumulator.ret.tr2
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; CHECK: case99:
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; CHECK-NOT: %recurse
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; CHECK: %accumulator.ret.tr = add i32 %accumulator.tr, 18
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; CHECK: %current.ret.tr = select i1 %ret.known.tr, i32 %ret.tr, i32 %accumulator.ret.tr
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; CHECK: default:
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; CHECK-NOT: %recurse
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; CHECK: %accumulate = add i32 %accumulator.tr, %y
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; It is only safe to transform one accumulator per function, make sure we don't
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; try to remove more.
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define i32 @test7_multiple_accumulators(i32 %a) local_unnamed_addr {
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entry:
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  %tobool = icmp eq i32 %a, 0
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  br i1 %tobool, label %return, label %if.end
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if.end:
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  %and = and i32 %a, 1
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  %tobool1 = icmp eq i32 %and, 0
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  %sub = add nsw i32 %a, -1
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  br i1 %tobool1, label %if.end3, label %if.then2
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if.then2:
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  %recurse1 = tail call i32 @test7_multiple_accumulators(i32 %sub)
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  %accumulate1 = add nsw i32 %recurse1, 1
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  br label %return
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if.end3:
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  %recurse2 = tail call i32 @test7_multiple_accumulators(i32 %sub)
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  %accumulate2 = mul nsw i32 %recurse2, 2
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  br label %return
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return:
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  %retval.0 = phi i32 [ %accumulate1, %if.then2 ], [ %accumulate2, %if.end3 ], [ 0, %entry ]
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  ret i32 %retval.0
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}
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; CHECK-LABEL: define i32 @test7_multiple_accumulators(
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; CHECK: tailrecurse:
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; CHECK: %accumulator.tr = phi i32 [ 0, %entry ], [ %accumulate1, %if.then2 ]
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; CHECK: if.then2:
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; CHECK-NOT: %recurse1
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; CHECK: %accumulate1 = add nsw i32 %accumulator.tr, 1
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; CHECK: if.end3:
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; CHECK: %recurse2
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; CHECK: %accumulator.ret.tr = add nsw i32 %accumulator.tr, %accumulate2
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; CHECK: ret i32 %accumulator.ret.tr
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; CHECK: return:
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; CHECK: %accumulator.ret.tr1 = add nsw i32 %accumulator.tr, 0
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; CHECK: ret i32 %accumulator.ret.tr1
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