[llvm-bugs] [Bug 48066] New: [AArch64] copy incorrectly erased and discard zero-extend operation

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=48066

            Bug ID: 48066
           Summary: [AArch64] copy incorrectly erased and discard
                    zero-extend operation
           Product: libraries
           Version: trunk
          Hardware: All
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P
         Component: Backend: AArch64
          Assignee: unassignedbugs at nondot.org
          Reporter: chengeng5 at huawei.com
                CC: arnaud.degrandmaison at arm.com,
                    llvm-bugs at lists.llvm.org, smithp352 at googlemail.com,
                    Ties.Stuij at arm.com

$ clang -O3 test-case.ll -w ;./a.out
c = -8917
$ clang -O0 test-case.ll -w ;./a.out
c = 4294958379


@b = dso_local local_unnamed_addr global { [3 x i8], i8, i8, i8, i8, i8 } { [3
x i8] undef, i8 -64, i8 74, i8 -9, i8 -1, i8 7 }, align 8
@c = common dso_local local_unnamed_addr global i64 0, align 8
@.str = private unnamed_addr constant [9 x i8] c"c = %ld\0A\00", align 1


define dso_local i8 @d(i64 %h) local_unnamed_addr {
entry:
  ret i8 undef
}

declare dso_local i32 @printf(i8* nocapture readonly, ...) local_unnamed_addr

define dso_local i32 @main() local_unnamed_addr {
entry:
  %bf.load = load i64, i64* bitcast ({ [3 x i8], i8, i8, i8, i8, i8 }* @b to
i64*), align 8
  %0 = lshr i64 %bf.load, 30
  %sext3 = shl nuw nsw i64 %0, 16
  %sext = trunc i64 %sext3 to i32
  %conv.i = ashr exact i32 %sext, 16
  %conv.i.i = zext i32 %conv.i to i64
  store i64 %conv.i.i, i64* @c, align 8
  %call.i.i = tail call i32 (i8*, ...) @printf(i8* nonnull dereferenceable(1)
getelementptr inbounds ([9 x i8], [9 x i8]* @.str, i64 0, i64 0), i64
%conv.i.i)
  %call4.i = tail call i8 bitcast (i8 (i64)* @d to i8 (i32, i32)*)(i32 0, i32
%conv.i)
  ret i32 0
}

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