; RUN: opt -O2 -mtriple=bpf-pc-linux -S -o - %s | FileCheck %s ; ; Check that bpf-preserve-static-offset folds chain of GEP instructions. ; The GEP chain in this example has type mismatch and thus is ; folded as i8 access. ; ; Source: ; #define __ctx __attribute__((preserve_static_offset)) ; ; struct foo { ; char aa; ; char bb; ; }; ; ; struct bar { ; char a; ; struct foo b; ; } __ctx; ; ; void buz(struct bar *p) { ; ((struct foo *)(((char*)&p->b) + 1))->bb = 42; ; } ; ; Compilation flag: ; clang -cc1 -O2 -triple bpf -S -emit-llvm -disable-llvm-passes -o - \ ; | opt -passes=function(sroa) -S -o - %struct.bar = type { i8, %struct.foo } %struct.foo = type { i8, i8 } ; Function Attrs: nounwind define dso_local void @buz(ptr noundef %p) #0 { entry: %0 = call ptr @llvm.preserve.static.offset(ptr %p) %b = getelementptr inbounds %struct.bar, ptr %0, i32 0, i32 1 %add.ptr = getelementptr inbounds i8, ptr %b, i64 1 ; ~~ ; these types do not match, thus GEP chain is folded as an offset ; ~~~~~~~~~~~ %bb = getelementptr inbounds %struct.foo, ptr %add.ptr, i32 0, i32 1 store i8 42, ptr %bb, align 1, !tbaa !2 ret void } ; CHECK: define dso_local void @buz(ptr nocapture noundef writeonly %[[p:.*]]) ; CHECK: tail call void (i8, ptr, i1, i8, i8, i8, i1, ...) ; CHECK-SAME: @llvm.bpf.getelementptr.and.store.i8 ; CHECK-SAME: (i8 42, ; CHECK-SAME: ptr writeonly elementtype(i8) %[[p]], ; CHECK-SAME: i1 false, i8 0, i8 1, i8 0, i1 true, i64 immarg 3) ; CHECK-SAME: #[[v2:.*]], !tbaa ![[v3:.*]] ; CHECK: attributes #[[v2]] = { memory(argmem: write) } ; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none) declare ptr @llvm.preserve.static.offset(ptr readnone) #1 attributes #0 = { nounwind "no-trapping-math"="true" "stack-protector-buffer-size"="8" } attributes #1 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) } !llvm.module.flags = !{!0} !llvm.ident = !{!1} !0 = !{i32 1, !"wchar_size", i32 4} !1 = !{!"clang"} !2 = !{!3, !4, i64 1} !3 = !{!"foo", !4, i64 0, !4, i64 1} !4 = !{!"omnipotent char", !5, i64 0} !5 = !{!"Simple C/C++ TBAA"}