[llvm] [X86] vector-shuffle-combining-avx512f.ll - add tests showing failure to simplify expand/compress nodes (PR #171113)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon created https://github.com/llvm/llvm-project/pull/171113

None

>From 81c3ab34ce82dd53a071c4b706111773aa7eb229 Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev at redking.me.uk>
Date: Mon, 8 Dec 2025 11:30:26 +0000
Subject: [PATCH] [X86] vector-shuffle-combining-avx512f.ll - add tests showing
 failure to simplify expand/compress nodes

---
 .../X86/vector-shuffle-combining-avx512f.ll   | 69 +++++++++++++++++++
 1 file changed, 69 insertions(+)

diff --git a/llvm/test/CodeGen/X86/vector-shuffle-combining-avx512f.ll b/llvm/test/CodeGen/X86/vector-shuffle-combining-avx512f.ll
index c33776daf18fa..3ea95eeaedfc7 100644
--- a/llvm/test/CodeGen/X86/vector-shuffle-combining-avx512f.ll
+++ b/llvm/test/CodeGen/X86/vector-shuffle-combining-avx512f.ll
@@ -22,6 +22,9 @@ declare <16 x float> @llvm.x86.avx512.mask.vpermi2var.ps.512(<16 x float>, <16 x
 declare <8 x i64> @llvm.x86.avx512.mask.vpermi2var.q.512(<8 x i64>, <8 x i64>, <8 x i64>, i8)
 declare <16 x i32> @llvm.x86.avx512.mask.vpermi2var.d.512(<16 x i32>, <16 x i32>, <16 x i32>, i16)
 
+declare <16 x i32> @llvm.x86.avx512.mask.expand.v16i32(<16 x i32>, <16 x i32>, <16 x i1>)
+declare <16 x i32> @llvm.x86.avx512.mask.compress.v16i32(<16 x i32>, <16 x i32>, <16 x i1>)
+
 define <8 x double> @combine_permvar_8f64_identity(<8 x double> %x0, <8 x double> %x1) {
 ; CHECK-LABEL: combine_permvar_8f64_identity:
 ; CHECK:       # %bb.0:
@@ -1031,3 +1034,69 @@ define <8 x double> @concat_vpermilvar_v8f64_v4f64(<4 x double> %a0, <4 x double
   %res = shufflevector <4 x double> %v0, <4 x double> %v1, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
   ret <8 x double> %res
 }
+
+; TODO - shift elements up by one
+define <16 x i32> @combine_vexpandd_as_valignd(<16 x i32>  %x) {
+; X86-AVX512F-LABEL: combine_vexpandd_as_valignd:
+; X86-AVX512F:       # %bb.0:
+; X86-AVX512F-NEXT:    movw $-2, %ax
+; X86-AVX512F-NEXT:    kmovw %eax, %k1
+; X86-AVX512F-NEXT:    vpexpandd %zmm0, %zmm0 {%k1} {z}
+; X86-AVX512F-NEXT:    retl
+;
+; X86-AVX512BW-LABEL: combine_vexpandd_as_valignd:
+; X86-AVX512BW:       # %bb.0:
+; X86-AVX512BW-NEXT:    movw $-2, %ax
+; X86-AVX512BW-NEXT:    kmovd %eax, %k1
+; X86-AVX512BW-NEXT:    vpexpandd %zmm0, %zmm0 {%k1} {z}
+; X86-AVX512BW-NEXT:    retl
+;
+; X64-AVX512F-LABEL: combine_vexpandd_as_valignd:
+; X64-AVX512F:       # %bb.0:
+; X64-AVX512F-NEXT:    movw $-2, %ax
+; X64-AVX512F-NEXT:    kmovw %eax, %k1
+; X64-AVX512F-NEXT:    vpexpandd %zmm0, %zmm0 {%k1} {z}
+; X64-AVX512F-NEXT:    retq
+;
+; X64-AVX512BW-LABEL: combine_vexpandd_as_valignd:
+; X64-AVX512BW:       # %bb.0:
+; X64-AVX512BW-NEXT:    movw $-2, %ax
+; X64-AVX512BW-NEXT:    kmovd %eax, %k1
+; X64-AVX512BW-NEXT:    vpexpandd %zmm0, %zmm0 {%k1} {z}
+; X64-AVX512BW-NEXT:    retq
+  %res = call <16 x i32> @llvm.x86.avx512.mask.expand.v16i32(<16 x i32> %x, <16 x i32> zeroinitializer, <16 x i1> <i1 false, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true>)
+  ret <16 x i32> %res
+}
+
+; TODO - zero upper half of vector
+define <16 x i32> @combine_vcompressd_as_vmov(<16 x i32> %x) {
+; X86-AVX512F-LABEL: combine_vcompressd_as_vmov:
+; X86-AVX512F:       # %bb.0:
+; X86-AVX512F-NEXT:    movw $255, %ax
+; X86-AVX512F-NEXT:    kmovw %eax, %k1
+; X86-AVX512F-NEXT:    vpcompressd %zmm0, %zmm0 {%k1} {z}
+; X86-AVX512F-NEXT:    retl
+;
+; X86-AVX512BW-LABEL: combine_vcompressd_as_vmov:
+; X86-AVX512BW:       # %bb.0:
+; X86-AVX512BW-NEXT:    movw $255, %ax
+; X86-AVX512BW-NEXT:    kmovd %eax, %k1
+; X86-AVX512BW-NEXT:    vpcompressd %zmm0, %zmm0 {%k1} {z}
+; X86-AVX512BW-NEXT:    retl
+;
+; X64-AVX512F-LABEL: combine_vcompressd_as_vmov:
+; X64-AVX512F:       # %bb.0:
+; X64-AVX512F-NEXT:    movw $255, %ax
+; X64-AVX512F-NEXT:    kmovw %eax, %k1
+; X64-AVX512F-NEXT:    vpcompressd %zmm0, %zmm0 {%k1} {z}
+; X64-AVX512F-NEXT:    retq
+;
+; X64-AVX512BW-LABEL: combine_vcompressd_as_vmov:
+; X64-AVX512BW:       # %bb.0:
+; X64-AVX512BW-NEXT:    movw $255, %ax
+; X64-AVX512BW-NEXT:    kmovd %eax, %k1
+; X64-AVX512BW-NEXT:    vpcompressd %zmm0, %zmm0 {%k1} {z}
+; X64-AVX512BW-NEXT:    retq
+  %res = call <16 x i32> @llvm.x86.avx512.mask.compress.v16i32(<16 x i32> %x, <16 x i32> zeroinitializer, <16 x i1> <i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 false, i1 false, i1 false, i1 false, i1 false, i1 false, i1 false, i1 false>)
+  ret <16 x i32> %res
+}