read-volatile-register.ll
702 Bytes
; RUN: opt -S -licm %s | FileCheck %s
; Volatile register shouldn't be hoisted ourside loops.
define i32 @test_read() {
; CHECK-LABEL: define i32 @test_read()
; CHECK: br label %loop
; CHECK: loop:
; CHECK: %counter = tail call i64 @llvm.read_volatile_register
entry:
br label %loop
loop:
%i = phi i32 [ 0, %entry ], [ %i.next, %inc ]
%counter = tail call i64 @llvm.read_volatile_register.i64(metadata !1)
%tst = icmp ult i64 %counter, 1000
br i1 %tst, label %inc, label %done
inc:
%i.next = add nuw nsw i32 %i, 1
br label %loop
done:
ret i32 %i
}
declare i64 @llvm.read_register.i64(metadata)
declare i64 @llvm.read_volatile_register.i64(metadata)
!1 = !{!"cntpct_el0"}