[llvm] [X86] Add test showing failure to concat X86ISD::PERMI nodes with different immediates (PR #203487)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon created https://github.com/llvm/llvm-project/pull/203487

None

>From 0a0ef911fb77b8e76b79adc3d209776a0554955a Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev at redking.me.uk>
Date: Fri, 12 Jun 2026 10:39:39 +0100
Subject: [PATCH] [X86] Add test showing failure to concat X86ISD::PERMI nodes
 with different immediates

---
 .../X86/vector-shuffle-combining-avx512f.ll      | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/llvm/test/CodeGen/X86/vector-shuffle-combining-avx512f.ll b/llvm/test/CodeGen/X86/vector-shuffle-combining-avx512f.ll
index 213445ca09005..9cdbce354ad37 100644
--- a/llvm/test/CodeGen/X86/vector-shuffle-combining-avx512f.ll
+++ b/llvm/test/CodeGen/X86/vector-shuffle-combining-avx512f.ll
@@ -1112,6 +1112,22 @@ define <16 x i32> @combine_vcompressd_splat(i16 %m) {
   ret <16 x i32> %res
 }
 
+define <8 x i64> @concat_nonuniform_permq_v4i64_v8i64(<4 x i64> %a0, <4 x i64> %a1, <2 x i64> %a2) nounwind {
+; CHECK-LABEL: concat_nonuniform_permq_v4i64_v8i64:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    vpermq {{.*#+}} ymm0 = ymm0[1,3,2,0]
+; CHECK-NEXT:    vpermq {{.*#+}} ymm1 = ymm1[3,2,1,0]
+; CHECK-NEXT:    vinserti64x4 $1, %ymm1, %zmm0, %zmm0
+; CHECK-NEXT:    vpsrlq %xmm2, %zmm0, %zmm0
+; CHECK-NEXT:    ret{{[l|q]}}
+  %perm0 = shufflevector <4 x i64> %a0, <4 x i64> poison, <4 x i32> <i32 1, i32 3, i32 2, i32 0>
+  %perm1 = shufflevector <4 x i64> %a1, <4 x i64> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+  %shift0 = tail call noundef <4 x i64> @llvm.x86.avx2.psrl.q(<4 x i64> %perm0, <2 x i64> %a2)
+  %shift1 = tail call noundef <4 x i64> @llvm.x86.avx2.psrl.q(<4 x i64> %perm1, <2 x i64> %a2)
+  %shuffle = shufflevector <4 x i64> %shift0, <4 x i64> %shift1, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
+  ret <8 x i64> %shuffle
+}
+
 define <8 x i64> @PR179008(ptr %p0) {
 ; X86-AVX512F-LABEL: PR179008:
 ; X86-AVX512F:       # %bb.0: