1; RUN: llc < %s -march=bpf -mattr=+alu32 -verify-machineinstrs | FileCheck %s 2; 3; Source: 4; struct __sk_buff { 5; unsigned data; 6; unsigned data_end; 7; }; 8; 9; void * test(int flag, struct __sk_buff *skb) 10; { 11; void *p; 12; 13; if (flag) { 14; p = (void *)(long)skb->data; 15; __asm__ __volatile__("": : :"memory"); 16; } else { 17; p = (void *)(long)skb->data_end; 18; __asm__ __volatile__("": : :"memory"); 19; } 20; 21; return p; 22; } 23; Compilation flag: 24; clang -target bpf -O2 -S -emit-llvm t.c 25 26%struct.__sk_buff = type { i32, i32 } 27 28define dso_local i8* @test(i32 %flag, %struct.__sk_buff* nocapture readonly %skb) local_unnamed_addr { 29entry: 30 %tobool = icmp eq i32 %flag, 0 31 br i1 %tobool, label %if.else, label %if.then 32 33if.then: 34 %data = getelementptr inbounds %struct.__sk_buff, %struct.__sk_buff* %skb, i64 0, i32 0 35 %0 = load i32, i32* %data, align 4 36 tail call void asm sideeffect "", "~{memory}"() 37 br label %if.end 38 39if.else: 40 %data_end = getelementptr inbounds %struct.__sk_buff, %struct.__sk_buff* %skb, i64 0, i32 1 41 %1 = load i32, i32* %data_end, align 4 42 tail call void asm sideeffect "", "~{memory}"() 43 br label %if.end 44 45if.end: 46 %p.0.in.in = phi i32 [ %0, %if.then ], [ %1, %if.else ] 47 %p.0.in = zext i32 %p.0.in.in to i64 48 %p.0 = inttoptr i64 %p.0.in to i8* 49 ret i8* %p.0 50} 51 52; CHECK: w0 = *(u32 *)(r2 + 0) 53; CHECK: w0 = *(u32 *)(r2 + 4) 54; CHECK-NOT: r[[#]] = w[[#]] 55; CHECK: exit 56