200 lines
		
	
	
		
			5.6 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			200 lines
		
	
	
		
			5.6 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; RUN: opt < %s -S -loop-unroll -unroll-threshold=30 | FileCheck %s
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; RUN: opt < %s -S -loop-unroll -unroll-threshold=30 -unroll-allow-peeling=false | FileCheck %s --check-prefix=DISABLE
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define i32 @invariant_backedge_1(i32 %a, i32 %b) {
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; CHECK-LABEL: @invariant_backedge_1
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; CHECK-NOT:     %plus = phi
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; CHECK:       loop.peel:
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; CHECK:       loop:
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; CHECK:         %i = phi
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; CHECK:         %sum = phi
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; DISABLE-LABEL: @invariant_backedge_1
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; DISABLE-NOT: loop.peel:
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entry:
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  br label %loop
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loop:
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  %i = phi i32 [ 0, %entry ], [ %inc, %loop ]
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  %sum = phi i32 [ 0, %entry ], [ %incsum, %loop ]
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  %plus = phi i32 [ %a, %entry ], [ %b, %loop ]
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  %incsum = add i32 %sum, %plus
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  %inc = add i32 %i, 1
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  %cmp = icmp slt i32 %i, 1000
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  br i1 %cmp, label %loop, label %exit
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exit:
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  ret i32 %sum
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}
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define i32 @invariant_backedge_2(i32 %a, i32 %b) {
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; This loop should be peeled twice because it has a Phi which becomes invariant
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; starting from 3rd iteration.
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; CHECK-LABEL: @invariant_backedge_2
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; CHECK:       loop.peel{{.*}}:
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; CHECK:       loop.peel{{.*}}:
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; CHECK:         %i = phi
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; CHECK:         %sum = phi
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; CHECK-NOT:     %half.inv = phi
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; CHECK-NOT:     %plus = phi
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entry:
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  br label %loop
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loop:
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  %i = phi i32 [ 0, %entry ], [ %inc, %loop ]
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  %sum = phi i32 [ 0, %entry ], [ %incsum, %loop ]
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  %half.inv = phi i32 [ %a, %entry ], [ %b, %loop ]
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  %plus = phi i32 [ %a, %entry ], [ %half.inv, %loop ]
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  %incsum = add i32 %sum, %plus
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  %inc = add i32 %i, 1
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  %cmp = icmp slt i32 %i, 1000
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  br i1 %cmp, label %loop, label %exit
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exit:
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  ret i32 %sum
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}
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define i32 @invariant_backedge_3(i32 %a, i32 %b) {
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; This loop should be peeled thrice because it has a Phi which becomes invariant
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; starting from 4th iteration.
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; CHECK-LABEL: @invariant_backedge_3
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; CHECK:       loop.peel{{.*}}:
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; CHECK:       loop.peel{{.*}}:
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; CHECK:       loop.peel{{.*}}:
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; CHECK:         %i = phi
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; CHECK:         %sum = phi
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; CHECK-NOT:     %half.inv = phi
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; CHECK-NOT:     %half.inv.2 = phi
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; CHECK-NOT:     %plus = phi
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entry:
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  br label %loop
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loop:
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  %i = phi i32 [ 0, %entry ], [ %inc, %loop ]
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  %sum = phi i32 [ 0, %entry ], [ %incsum, %loop ]
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  %half.inv = phi i32 [ %a, %entry ], [ %b, %loop ]
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  %half.inv.2 = phi i32 [ %a, %entry ], [ %half.inv, %loop ]
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  %plus = phi i32 [ %a, %entry ], [ %half.inv.2, %loop ]
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  %incsum = add i32 %sum, %plus
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  %inc = add i32 %i, 1
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  %cmp = icmp slt i32 %i, 1000
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  br i1 %cmp, label %loop, label %exit
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exit:
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  ret i32 %sum
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}
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define i32 @invariant_backedge_limited_by_size(i32 %a, i32 %b) {
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; This loop should normally be peeled thrice because it has a Phi which becomes
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; invariant starting from 4th iteration, but the size of the loop only allows
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; us to peel twice because we are restricted to 30 instructions in resulting
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; code. Thus, %plus Phi node should stay in loop even despite its backedge
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; input is an invariant.
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; CHECK-LABEL: @invariant_backedge_limited_by_size
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; CHECK:       loop.peel{{.*}}:
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; CHECK:       loop.peel{{.*}}:
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; CHECK:         %i = phi
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; CHECK:         %sum = phi
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; CHECK:         %plus = phi i32 [ %a, {{.*}} ], [ %b, %loop ]
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; CHECK-NOT:     %half.inv = phi
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; CHECK-NOT:     %half.inv.2 = phi
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entry:
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  br label %loop
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loop:
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  %i = phi i32 [ 0, %entry ], [ %inc, %loop ]
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  %sum = phi i32 [ 0, %entry ], [ %incsum, %loop ]
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  %half.inv = phi i32 [ %a, %entry ], [ %b, %loop ]
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  %half.inv.2 = phi i32 [ %a, %entry ], [ %half.inv, %loop ]
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  %plus = phi i32 [ %a, %entry ], [ %half.inv.2, %loop ]
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  %incsum = add i32 %sum, %plus
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  %inc = add i32 %i, 1
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  %cmp = icmp slt i32 %i, 1000
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  %incsum2 = add i32 %incsum, %plus
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  %incsum3 = add i32 %incsum, %plus
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  %incsum4 = add i32 %incsum, %plus
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  %incsum5 = add i32 %incsum, %plus
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  %incsum6 = add i32 %incsum, %plus
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  %incsum7 = add i32 %incsum, %plus
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  br i1 %cmp, label %loop, label %exit
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exit:
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  ret i32 %sum
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}
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; Peeling should fail due to method size.
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define i32 @invariant_backedge_negative(i32 %a, i32 %b) {
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; CHECK-LABEL: @invariant_backedge_negative
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; CHECK-NOT:   loop.peel{{.*}}:
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; CHECK:       loop:
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; CHECK:         %i = phi
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; CHECK:         %sum = phi
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; CHECK:         %plus = phi
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entry:
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  br label %loop
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loop:
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  %i = phi i32 [ 0, %entry ], [ %inc, %loop ]
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  %sum = phi i32 [ 0, %entry ], [ %incsum2, %loop ]
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  %plus = phi i32 [ %a, %entry ], [ %b, %loop ]
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  %incsum = add i32 %sum, %plus
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  %incsum2 = add i32 %incsum, %plus
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  %incsum3 = add i32 %incsum, %plus
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  %incsum4 = add i32 %incsum, %plus
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  %incsum5 = add i32 %incsum, %plus
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  %incsum6 = add i32 %incsum, %plus
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  %incsum7 = add i32 %incsum, %plus
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  %incsum8 = add i32 %incsum, %plus
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  %incsum9 = add i32 %incsum, %plus
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  %incsum10 = add i32 %incsum, %plus
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  %incsum11 = add i32 %incsum, %plus
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  %incsum12 = add i32 %incsum, %plus
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  %incsum13 = add i32 %incsum, %plus
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  %incsum14 = add i32 %incsum, %plus
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  %incsum15 = add i32 %incsum, %plus
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  %inc = add i32 %i, 1
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  %cmp = icmp slt i32 %i, 1000
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  br i1 %cmp, label %loop, label %exit
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exit:
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  ret i32 %sum
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}
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define i32 @cycled_phis(i32 %a, i32 %b) {
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; Make sure that we do not crash working with cycled Phis and don't peel it.
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; TODO: Actually this loop should be partially unrolled with factor 2.
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; CHECK-LABEL: @cycled_phis
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; CHECK-NOT:   loop.peel{{.*}}:
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; CHECK:       loop:
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; CHECK:         %i = phi
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; CHECK:         %phi.a = phi
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; CHECK:         %phi.b = phi
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; CHECK:         %sum = phi
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entry:
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  br label %loop
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loop:
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  %i = phi i32 [ 0, %entry ], [ %inc, %loop ]
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  %phi.a = phi i32 [ %a, %entry ], [ %phi.b, %loop ]
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  %phi.b = phi i32 [ %b, %entry ], [ %phi.a, %loop ]
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  %sum = phi i32 [ 0, %entry], [ %incsum, %loop ]
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  %incsum = add i32 %sum, %phi.a
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  %inc = add i32 %i, 1
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  %cmp = icmp slt i32 %i, 1000
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  br i1 %cmp, label %loop, label %exit
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exit:
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  ret i32 %sum
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}
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