1; RUN: opt -passes=bpf-preserve-static-offset -mtriple=bpf-pc-linux -S -o - %s | FileCheck %s 2; 3; Check that loads from zero offset are not modified by bpf-preserve-static-offset. 4; 5; Source: 6; #define __ctx __attribute__((preserve_static_offset)) 7; 8; struct foo { 9; int a; 10; } __ctx; 11; 12; extern void consume(int); 13; 14; void bar(struct foo *p) { 15; consume(p->a); 16; } 17; 18; Compilation flag: 19; clang -cc1 -O2 -triple bpf -S -emit-llvm -disable-llvm-passes -o - \ 20; | opt -passes=function(sroa) -S -o - 21 22%struct.foo = type { i32 } 23 24; Function Attrs: nounwind 25define dso_local void @bar(ptr noundef %p) #0 { 26entry: 27 %0 = call ptr @llvm.preserve.static.offset(ptr %p) 28 %a = getelementptr inbounds %struct.foo, ptr %0, i32 0, i32 0 29 %1 = load i32, ptr %a, align 4, !tbaa !2 30 call void @consume(i32 noundef %1) 31 ret void 32} 33 34; CHECK: entry: 35; CHECK-NEXT: %[[a:.*]] = getelementptr inbounds %struct.foo, ptr %[[p:.*]], i32 0, i32 0 36; CHECK-NEXT: %[[v2:.*]] = load i32, ptr %[[a]], align 4, !tbaa 37; CHECK-NEXT: call void @consume(i32 noundef %[[v2]]) 38 39declare void @consume(i32 noundef) #1 40 41; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none) 42declare ptr @llvm.preserve.static.offset(ptr readnone) #2 43 44attributes #0 = { nounwind "no-trapping-math"="true" "stack-protector-buffer-size"="8" } 45attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" } 46attributes #2 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) } 47 48!llvm.module.flags = !{!0} 49!llvm.ident = !{!1} 50 51!0 = !{i32 1, !"wchar_size", i32 4} 52!1 = !{!"clang"} 53!2 = !{!3, !4, i64 0} 54!3 = !{!"foo", !4, i64 0} 55!4 = !{!"int", !5, i64 0} 56!5 = !{!"omnipotent char", !6, i64 0} 57!6 = !{!"Simple C/C++ TBAA"} 58