141 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			141 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; RUN: llc -O2 -o - %s | FileCheck %s
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target datalayout = "e-m:e-i64:64-n32:64"
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target triple = "powerpc64le-grtev4-linux-gnu"
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; Intended layout:
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; The code for tail-duplication during layout will produce the layout:
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; test1
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; test2
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; body1 (with copy of test2)
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; body2
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; exit
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;CHECK-LABEL: tail_dup_break_cfg:
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;CHECK: mr [[TAGREG:[0-9]+]], 3
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;CHECK: andi. {{[0-9]+}}, [[TAGREG]], 1
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;CHECK-NEXT: bc 12, 1, [[BODY1LABEL:[._0-9A-Za-z]+]]
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;CHECK-NEXT: # %test2
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;CHECK-NEXT: andi. {{[0-9]+}}, [[TAGREG]], 2
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;CHECK-NEXT: bne 0, [[BODY2LABEL:[._0-9A-Za-z]+]]
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;CHECK: [[EXITLABEL:[._0-9A-Za-z]+]]: # %exit
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;CHECK: blr
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;CHECK-NEXT: [[BODY1LABEL]]
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;CHECK: andi. {{[0-9]+}}, [[TAGREG]], 2
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;CHECK-NEXT: beq 0, [[EXITLABEL]]
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;CHECK-NEXT: [[BODY2LABEL:[._0-9A-Za-z]+]]:
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;CHECK: b [[EXITLABEL]]
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define void @tail_dup_break_cfg(i32 %tag) {
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entry:
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  br label %test1
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test1:
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  %tagbit1 = and i32 %tag, 1
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  %tagbit1eq0 = icmp eq i32 %tagbit1, 0
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  br i1 %tagbit1eq0, label %test2, label %body1, !prof !1 ; %test2 more likely
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body1:
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  call void @a()
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  call void @a()
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  call void @a()
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  call void @a()
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  br label %test2
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test2:
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  %tagbit2 = and i32 %tag, 2
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  %tagbit2eq0 = icmp eq i32 %tagbit2, 0
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  br i1 %tagbit2eq0, label %exit, label %body2, !prof !1 ; %exit more likely
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body2:
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  call void @b()
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  call void @b()
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  call void @b()
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  call void @b()
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  br label %exit
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exit:
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  ret void
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}
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; The branch weights here hint that we shouldn't tail duplicate in this case.
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;CHECK-LABEL: tail_dup_dont_break_cfg:
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;CHECK: mr [[TAGREG:[0-9]+]], 3
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;CHECK: andi. {{[0-9]+}}, [[TAGREG]], 1
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;CHECK-NEXT: bc 4, 1, [[TEST2LABEL:[._0-9A-Za-z]+]]
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;CHECK-NEXT: # %body1
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;CHECK: [[TEST2LABEL]]: # %test2
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;CHECK-NEXT: andi. {{[0-9]+}}, [[TAGREG]], 2
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;CHECK-NEXT: beq 0, [[EXITLABEL:[._0-9A-Za-z]+]]
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;CHECK-NEXT: # %body2
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;CHECK: [[EXITLABEL:[._0-9A-Za-z]+]]: # %exit
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;CHECK: blr
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define void @tail_dup_dont_break_cfg(i32 %tag) {
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entry:
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  br label %test1
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test1:
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  %tagbit1 = and i32 %tag, 1
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  %tagbit1eq0 = icmp eq i32 %tagbit1, 0
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  br i1 %tagbit1eq0, label %test2, label %body1, !prof !1 ; %test2 more likely
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body1:
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  call void @a()
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  call void @a()
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  call void @a()
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  call void @a()
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  br label %test2
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test2:
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  %tagbit2 = and i32 %tag, 2
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  %tagbit2eq0 = icmp ne i32 %tagbit2, 0
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  br i1 %tagbit2eq0, label %body2, label %exit, !prof !3 ; %body2 more likely
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body2:
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  call void @b()
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  call void @b()
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  call void @b()
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  call void @b()
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  br label %exit
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exit:
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  ret void
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}
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declare void @a()
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declare void @b()
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declare void @c()
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declare void @d()
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; This function arranges for the successors of %succ to have already been laid
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; out. When we consider whether to lay out succ after bb and to tail-duplicate
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; it, v and ret have already been placed, so we tail-duplicate as it removes a
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; branch and strictly increases fallthrough
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; CHECK-LABEL: tail_dup_no_succ
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; CHECK: # %entry
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; CHECK: # %v
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; CHECK: # %ret
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; CHECK: # %bb
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; CHECK: # %succ
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; CHECK: # %c
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; CHECK: bl c
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; CHECK: andi. {{[0-9]+}}, {{[0-9]+}}, 4
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; CHECK: beq
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; CHECK: b
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define void @tail_dup_no_succ(i32 %tag) {
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entry:
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  %tagbit1 = and i32 %tag, 1
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  %tagbit1eq0 = icmp eq i32 %tagbit1, 0
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  br i1 %tagbit1eq0, label %v, label %bb, !prof !2 ; %v very much more likely
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bb:
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  %tagbit2 = and i32 %tag, 2
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  %tagbit2eq0 = icmp eq i32 %tagbit2, 0
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  br i1 %tagbit2eq0, label %succ, label %c, !prof !3 ; %succ more likely
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c:
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  call void @c()
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  call void @c()
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  br label %succ
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succ:
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  %tagbit3 = and i32 %tag, 4
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  %tagbit3eq0 = icmp eq i32 %tagbit3, 0
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  br i1 %tagbit3eq0, label %ret, label %v, !prof !1 ; %u more likely
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v:
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  call void @d()
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  call void @d()
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  br label %ret
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ret:
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  ret void
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}
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!1 = !{!"branch_weights", i32 5, i32 3}
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!2 = !{!"branch_weights", i32 95, i32 5}
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!3 = !{!"branch_weights", i32 8, i32 3}
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