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4f63cbd37f
As commented on the existing code: // The Reg operand should be a virtual register, which is defined // outside the current basic block. DAG combiner has done a pretty // good job in removing truncating inside a single basic block. However, when the Reg operand comes from bpf_load_[byte | half | word] intrinsics, the generic optimizer doesn't understand their results are zero extended, so these single basic block elimination opportunities were missed. Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Jiong Wang <jiong.wang@netronome.com> llvm-svn: 322534
59 lines
1.5 KiB
LLVM
59 lines
1.5 KiB
LLVM
; RUN: llc < %s -march=bpf -verify-machineinstrs | FileCheck %s
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; Source code:
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;struct __sk_buff;
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;unsigned long long
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;load_byte(void *skb, unsigned long long off) asm("llvm.bpf.load.byte");
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;unsigned long long
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;load_half(void *skb, unsigned long long off) asm("llvm.bpf.load.half");
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;typedef unsigned char uint8_t;
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;typedef unsigned short uint16_t;
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;
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;int func_b(struct __sk_buff *skb)
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;{
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; uint8_t t = load_byte(skb, 0);
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; return t;
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;}
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;
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;int func_h(struct __sk_buff *skb)
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;{
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; uint16_t t = load_half(skb, 0);
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; return t;
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;}
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;
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;int func_w(struct __sk_buff *skb)
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;{
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; uint32_t t = load_word(skb, 0);
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; return t;
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;}
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%struct.__sk_buff = type opaque
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; Function Attrs: nounwind readonly
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define i32 @func_b(%struct.__sk_buff* %skb) local_unnamed_addr #0 {
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entry:
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%0 = bitcast %struct.__sk_buff* %skb to i8*
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%call = tail call i64 @llvm.bpf.load.byte(i8* %0, i64 0)
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%conv = trunc i64 %call to i32
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%conv1 = and i32 %conv, 255
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; CHECK-NOT: r0 &= 255
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ret i32 %conv1
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}
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; Function Attrs: nounwind readonly
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declare i64 @llvm.bpf.load.byte(i8*, i64) #1
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; Function Attrs: nounwind readonly
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define i32 @func_h(%struct.__sk_buff* %skb) local_unnamed_addr #0 {
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entry:
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%0 = bitcast %struct.__sk_buff* %skb to i8*
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%call = tail call i64 @llvm.bpf.load.half(i8* %0, i64 0)
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%conv = trunc i64 %call to i32
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%conv1 = and i32 %conv, 65535
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; CHECK-NOT: r0 &= 65535
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ret i32 %conv1
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}
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; Function Attrs: nounwind readonly
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declare i64 @llvm.bpf.load.half(i8*, i64) #1
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