LLVM insertvalue bad optimized? - optimization

Question

Should I avoid using the 'insertvalue' instruction combined with load and store when I emit LLVM code?
I always get bad optimized native code when I use it. Look at the following example:
; ModuleID = 'mod'
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
target triple = "x86_64-pc-linux-gnu"
%A = type { i64, i64, i64, i64, i64, i64, i64, i64 }
#aa = external global %A*
define void #func() {
entry:
%a1 = load %A** #aa
%a2 = load %A* %a1
%a3 = insertvalue %A %a2, i64 3, 3
store %A %a3, %A* %a1
ret void
}
When I run "llc -o - -O3 mod.ll", I get this horrible code:
func: # #func
.Ltmp0:
.cfi_startproc
# BB#0: # %entry
movq aa(%rip), %rax
movq (%rax), %r8
movq 8(%rax), %r9
movq 16(%rax), %r10
movq 32(%rax), %rdi
movq 40(%rax), %rcx
movq 48(%rax), %rdx
movq 56(%rax), %rsi
movq %rsi, 56(%rax)
movq %rdx, 48(%rax)
movq %rcx, 40(%rax)
movq %rdi, 32(%rax)
movq %r10, 16(%rax)
movq %r9, 8(%rax)
movq %r8, (%rax)
movq $3, 24(%rax)
ret
But what I would like to see is this:
func: # #func
.Ltmp0:
.cfi_startproc
# BB#0: # %entry
movq aa(%rip), %rax
movq $3, 24(%rax)
ret
Of course I can use getelementptr or something, but sometimes it is easier to generate insertvalue and extractvalue instructions, and I want these to be optimized...
I think it would be quite easy for the codegen to see that things like these are bad:
movq 56(%rax), %rsi
movq %rsi, 56(%rax)

Answer 1

First, note that llc does not do any IR-level optimizations. So, you should run opt to run the set of IR-level optimizers.
However, opt does not help in this. I'd expect that standard IR-level optimizers canonicalize the stuff into gep somehow.
Please file a LLVM PR, this looks like a missed optimization!