52 lines
		
	
	
		
			1.1 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			52 lines
		
	
	
		
			1.1 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; RUN: opt -S < %s -gvn | FileCheck %s
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declare void @llvm.sideeffect()
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; Store-to-load forwarding across a @llvm.sideeffect.
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; CHECK-LABEL: s2l
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; CHECK-NOT: load
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define float @s2l(float* %p) {
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    store float 0.0, float* %p
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    call void @llvm.sideeffect()
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    %t = load float, float* %p
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    ret float %t
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}
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; Redundant load elimination across a @llvm.sideeffect.
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; CHECK-LABEL: rle
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; CHECK: load
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; CHECK-NOT: load
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define float @rle(float* %p) {
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    %r = load float, float* %p
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    call void @llvm.sideeffect()
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    %s = load float, float* %p
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    %t = fadd float %r, %s
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    ret float %t
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}
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; LICM across a @llvm.sideeffect.
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; CHECK-LABEL: licm
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; CHECK: load
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; CHECK: loop:
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; CHECK-NOT: load
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define float @licm(i64 %n, float* nocapture readonly %p) #0 {
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bb0:
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  br label %loop
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loop:
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  %i = phi i64 [ 0, %bb0 ], [ %t5, %loop ]
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  %sum = phi float [ 0.000000e+00, %bb0 ], [ %t4, %loop ]
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  call void @llvm.sideeffect()
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  %t3 = load float, float* %p
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  %t4 = fadd float %sum, %t3
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  %t5 = add i64 %i, 1
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  %t6 = icmp ult i64 %t5, %n
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  br i1 %t6, label %loop, label %bb2
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bb2:
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  ret float %t4
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}
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