[llvm] [NFC] NFC patch to lockdown instructions of vspltisw for addition of vector of 1s (PR #160476)

[via llvm-commits]

https://github.com/Himadhith updated https://github.com/llvm/llvm-project/pull/160476

>From 908c6b89967a9ee94d1e52abc11d8814b8374219 Mon Sep 17 00:00:00 2001
From: himadhith <himadhith.v at ibm.com>
Date: Wed, 24 Sep 2025 09:36:23 +0000
Subject: [PATCH] [NFC] NFC patch to lockdown instructions of vspltisw for
 addition of vector of 1s

---
 llvm/test/CodeGen/PowerPC/vector-all-ones.ll | 35 ++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 llvm/test/CodeGen/PowerPC/vector-all-ones.ll

diff --git a/llvm/test/CodeGen/PowerPC/vector-all-ones.ll b/llvm/test/CodeGen/PowerPC/vector-all-ones.ll
new file mode 100644
index 0000000000000..0fa4b3417245a
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/vector-all-ones.ll
@@ -0,0 +1,35 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 6
+; RUN: llc -verify-machineinstrs -O3 -mcpu=pwr9 -mtriple=powerpc64le-unknown-linux-gnu \
+; RUN:     -ppc-asm-full-reg-names --ppc-vsr-nums-as-vr < %s | FileCheck %s --check-prefix=POWERPC_64LE
+
+; RUN: llc -verify-machineinstrs -O3 -mcpu=pwr9 -mtriple=powerpc64-ibm-aix \
+; RUN:     -ppc-asm-full-reg-names --ppc-vsr-nums-as-vr < %s | FileCheck %s --check-prefix=POWERPC_64
+
+; RUN: llc -verify-machineinstrs -O3 -mcpu=pwr9 -mtriple=powerpc-ibm-aix \
+; RUN:     -ppc-asm-full-reg-names --ppc-vsr-nums-as-vr < %s | FileCheck %s --check-prefix=POWERPC_32
+
+; Currently the generated code uses `vspltisw` to generate vector of 1s followed by add operation.
+; This pattern is expected to be optimized in a future patch by using `xxleqv` to generate vector of -1s
+; followed by subtraction operation.
+define dso_local noundef <4 x i32> @test1(<4 x i32> %a) {
+; POWERPC_64LE-LABEL: test1:
+; POWERPC_64LE:       # %bb.0: # %entry
+; POWERPC_64LE-NEXT:    vspltisw v3, 1
+; POWERPC_64LE-NEXT:    vadduwm v2, v2, v3
+; POWERPC_64LE-NEXT:    blr
+;
+; POWERPC_64-LABEL: test1:
+; POWERPC_64:       # %bb.0: # %entry
+; POWERPC_64-NEXT:    vspltisw v3, 1
+; POWERPC_64-NEXT:    vadduwm v2, v2, v3
+; POWERPC_64-NEXT:    blr
+;
+; POWERPC_32-LABEL: test1:
+; POWERPC_32:       # %bb.0: # %entry
+; POWERPC_32-NEXT:    vspltisw v3, 1
+; POWERPC_32-NEXT:    vadduwm v2, v2, v3
+; POWERPC_32-NEXT:    blr
+entry:
+  %add = add <4 x i32> %a, splat (i32 1)
+  ret <4 x i32> %add
+}