[llvm] [LoongArch] Optimize extractelement containing variable index (PR #151475)

[via llvm-commits]

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@@ -176,21 +135,10 @@ define void @extract_4xi64_idx(ptr %src, ptr %dst, i32 %idx) nounwind {
 define void @extract_8xfloat_idx(ptr %src, ptr %dst, i32 %idx) nounwind {
 ; CHECK-LABEL: extract_8xfloat_idx:
 ; CHECK:       # %bb.0:
-; CHECK-NEXT:    addi.d $sp, $sp, -96
-; CHECK-NEXT:    st.d $ra, $sp, 88 # 8-byte Folded Spill
-; CHECK-NEXT:    st.d $fp, $sp, 80 # 8-byte Folded Spill
-; CHECK-NEXT:    addi.d $fp, $sp, 96
-; CHECK-NEXT:    bstrins.d $sp, $zero, 4, 0
 ; CHECK-NEXT:    xvld $xr0, $a0, 0
-; CHECK-NEXT:    xvst $xr0, $sp, 32
-; CHECK-NEXT:    addi.d $a0, $sp, 32
-; CHECK-NEXT:    bstrins.d $a0, $a2, 4, 2
-; CHECK-NEXT:    fld.s $fa0, $a0, 0
-; CHECK-NEXT:    fst.s $fa0, $a1, 0
-; CHECK-NEXT:    addi.d $sp, $fp, -96
-; CHECK-NEXT:    ld.d $fp, $sp, 80 # 8-byte Folded Reload
-; CHECK-NEXT:    ld.d $ra, $sp, 88 # 8-byte Folded Reload
-; CHECK-NEXT:    addi.d $sp, $sp, 96
+; CHECK-NEXT:    xvreplgr2vr.w $xr1, $a2
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tangaac wrote:

LGTM
It seems this `xvreplgr2vr` could be replaced.
Fot LSX, your optimization may work too.

https://github.com/llvm/llvm-project/pull/151475