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|
; RUN: opt -passes=bpf-preserve-static-offset -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 unexpected shape and thus is
; folded as i8 access.
;
; Source (IR modified by hand):
; #define __ctx __attribute__((preserve_static_offset))
;
; struct foo {
; char a[2];
; };
;
; struct bar {
; char a;
; struct foo b;
; } __ctx;
;
; extern void consume(char);
;
; void buz(struct bar *p) {
; consume((&p->b)[1].a[1]);
; }
;
; Compilation flag:
; clang -cc1 -O2 -triple bpf -S -emit-llvm -disable-llvm-passes -o - \
; | opt -passes=function(sroa) -S -o -
;
; Modified to remove 'inbounds' from one of the GEP instructions.
%struct.bar = type { i8, %struct.foo }
%struct.foo = type { [2 x 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
%arrayidx = getelementptr inbounds %struct.foo, ptr %b, i64 1
; ^^^^^
; folded as i8 access because of this index
%a = getelementptr %struct.foo, ptr %arrayidx, i32 0, i32 0
%arrayidx1 = getelementptr inbounds [2 x i8], ptr %a, i64 0, i64 1
%1 = load i8, ptr %arrayidx1, align 1, !tbaa !2
call void @consume(i8 noundef signext %1)
ret void
}
; CHECK: %[[v1:.*]] = call i8 (ptr, i1, i8, i8, i8, i1, ...)
; CHECK-SAME: @llvm.bpf.getelementptr.and.load.i8
; CHECK-SAME: (ptr readonly elementtype(i8) %{{[^,]+}},
; CHECK-SAME: i1 false, i8 0, i8 1, i8 0, i1 false, i64 immarg 4)
; ^^^^^^^^ ^^^^^^^^^^^^
; not inbounds ---' |
; offset from 'struct bar' start -------------'
; CHECK-NEXT: call void @consume(i8 noundef signext %[[v1]])
declare void @consume(i8 noundef signext) #1
; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare ptr @llvm.preserve.static.offset(ptr readnone) #2
attributes #0 = { nounwind "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
attributes #2 = { 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, !3, i64 0}
!3 = !{!"omnipotent char", !4, i64 0}
!4 = !{!"Simple C/C++ TBAA"}
|
