56 lines
		
	
	
		
			1.4 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			56 lines
		
	
	
		
			1.4 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; RUN: llc < %s -march=bpf -mattr=+alu32 -verify-machineinstrs | FileCheck %s
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;
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; Source:
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;  struct __sk_buff {
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;    unsigned data;
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;    unsigned data_end;
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;  };
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;
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;  void * test(int flag, struct __sk_buff *skb)
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;  {
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;    void *p;
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;
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;    if (flag) {
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;      p = (void *)(long)skb->data;
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;      __asm__ __volatile__("": : :"memory");
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;    } else {
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;      p = (void *)(long)skb->data_end;
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;      __asm__ __volatile__("": : :"memory");
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;    }
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;
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;    return p;
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;  }
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; Compilation flag:
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;   clang -target bpf -O2 -S -emit-llvm t.c
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%struct.__sk_buff = type { i32, i32 }
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define dso_local i8* @test(i32 %flag, %struct.__sk_buff* nocapture readonly %skb) local_unnamed_addr {
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entry:
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  %tobool = icmp eq i32 %flag, 0
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  br i1 %tobool, label %if.else, label %if.then
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if.then:
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  %data = getelementptr inbounds %struct.__sk_buff, %struct.__sk_buff* %skb, i64 0, i32 0
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  %0 = load i32, i32* %data, align 4
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  tail call void asm sideeffect "", "~{memory}"()
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  br label %if.end
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if.else:
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  %data_end = getelementptr inbounds %struct.__sk_buff, %struct.__sk_buff* %skb, i64 0, i32 1
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  %1 = load i32, i32* %data_end, align 4
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  tail call void asm sideeffect "", "~{memory}"()
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  br label %if.end
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if.end:
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  %p.0.in.in = phi i32 [ %0, %if.then ], [ %1, %if.else ]
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  %p.0.in = zext i32 %p.0.in.in to i64
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  %p.0 = inttoptr i64 %p.0.in to i8*
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  ret i8* %p.0
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}
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; CHECK:       w0 = *(u32 *)(r2 + 0)
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; CHECK:       w0 = *(u32 *)(r2 + 4)
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; CHECK-NOT:   r[[#]] = w[[#]]
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; CHECK:       exit
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