[llvm] [X86] vselect-pcmp.ll - add test showing failure to fold icmp_eq(and(x,pow2),0) to shl(x,c) for v4f32 select masks (PR #173359)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon created https://github.com/llvm/llvm-project/pull/173359

Noticed while trying to tweak backend folds to workaround #172888

>From 45c25d2b3fdc4fb9adcb5b1ace0e3ef30a087019 Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev at redking.me.uk>
Date: Tue, 23 Dec 2025 11:20:28 +0000
Subject: [PATCH] [X86] vselect-pcmp.ll - add test showing failure to fold
 icmp_eq(and(x,pow2),0) to shl(x,c) for v4f32 select masks

Noticed while trying to tweak backend folds to workaround #172888
---
 llvm/test/CodeGen/X86/vselect-pcmp.ll | 48 +++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/llvm/test/CodeGen/X86/vselect-pcmp.ll b/llvm/test/CodeGen/X86/vselect-pcmp.ll
index 16700d42ad448..8e6c4d83c7617 100644
--- a/llvm/test/CodeGen/X86/vselect-pcmp.ll
+++ b/llvm/test/CodeGen/X86/vselect-pcmp.ll
@@ -544,6 +544,54 @@ define <4 x i64> @blend_splat1_mask_cond_v4i64(<4 x i64> %x, <4 x i64> %y, <4 x
   ret <4 x i64> %r
 }
 
+; FIXME: use PSLLD(Z,31) like blend_splat1_mask_cond_v4i32
+define <4 x float> @blend_splat1_mask_cond_v4f32(<4 x i32> %x, <4 x float> %y, <4 x float> %z) {
+; AVX1-LABEL: blend_splat1_mask_cond_v4f32:
+; AVX1:       # %bb.0:
+; AVX1-NEXT:    vbroadcastss {{.*#+}} xmm3 = [1,1,1,1]
+; AVX1-NEXT:    vpand %xmm3, %xmm0, %xmm0
+; AVX1-NEXT:    vpcmpeqd %xmm3, %xmm0, %xmm0
+; AVX1-NEXT:    vblendvps %xmm0, %xmm2, %xmm1, %xmm0
+; AVX1-NEXT:    retq
+;
+; AVX2-LABEL: blend_splat1_mask_cond_v4f32:
+; AVX2:       # %bb.0:
+; AVX2-NEXT:    vpbroadcastd {{.*#+}} xmm3 = [1,1,1,1]
+; AVX2-NEXT:    vpand %xmm3, %xmm0, %xmm0
+; AVX2-NEXT:    vpcmpeqd %xmm3, %xmm0, %xmm0
+; AVX2-NEXT:    vblendvps %xmm0, %xmm2, %xmm1, %xmm0
+; AVX2-NEXT:    retq
+;
+; AVX512F-LABEL: blend_splat1_mask_cond_v4f32:
+; AVX512F:       # %bb.0:
+; AVX512F-NEXT:    # kill: def $xmm2 killed $xmm2 def $zmm2
+; AVX512F-NEXT:    # kill: def $xmm1 killed $xmm1 def $zmm1
+; AVX512F-NEXT:    # kill: def $xmm0 killed $xmm0 def $zmm0
+; AVX512F-NEXT:    vptestnmd {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to16}, %zmm0, %k1
+; AVX512F-NEXT:    vblendmps %zmm1, %zmm2, %zmm0 {%k1}
+; AVX512F-NEXT:    # kill: def $xmm0 killed $xmm0 killed $zmm0
+; AVX512F-NEXT:    vzeroupper
+; AVX512F-NEXT:    retq
+;
+; AVX512VL-LABEL: blend_splat1_mask_cond_v4f32:
+; AVX512VL:       # %bb.0:
+; AVX512VL-NEXT:    vptestnmd {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to4}, %xmm0, %k1
+; AVX512VL-NEXT:    vblendmps %xmm1, %xmm2, %xmm0 {%k1}
+; AVX512VL-NEXT:    retq
+;
+; XOP-LABEL: blend_splat1_mask_cond_v4f32:
+; XOP:       # %bb.0:
+; XOP-NEXT:    vpand {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0, %xmm0
+; XOP-NEXT:    vpxor %xmm3, %xmm3, %xmm3
+; XOP-NEXT:    vpcomeqd %xmm3, %xmm0, %xmm0
+; XOP-NEXT:    vblendvps %xmm0, %xmm1, %xmm2, %xmm0
+; XOP-NEXT:    retq
+  %a = and <4 x i32> %x, <i32 1, i32 1, i32 1, i32 1>
+  %c = icmp eq <4 x i32> %a, zeroinitializer
+  %r = select <4 x i1> %c, <4 x float> %y, <4 x float> %z
+  ret <4 x float> %r
+}
+
 define <4 x i32> @blend_splat1_mask_cond_v4i32(<4 x i32> %x, <4 x i32> %y, <4 x i32> %z) {
 ; AVX12-LABEL: blend_splat1_mask_cond_v4i32:
 ; AVX12:       # %bb.0: