[clang] [CIR][CIRGen][Builtin][X86] Multishift Intrinsics (PR #169618)

[Omkar Rasal via cfe-commits]

https://github.com/cs25mtech12008 created https://github.com/llvm/llvm-project/pull/169618

Added builtin support for the multishift operation with test file.

changes has been done in CIRGenBuiltinX86 file

>From 94c0ba39a38452aec34157c44f1bbc8eb458b65b Mon Sep 17 00:00:00 2001
From: cs25mtech12008 <cs25mtech12008 at iith.ac.in>
Date: Wed, 26 Nov 2025 12:47:53 +0530
Subject: [PATCH] [CIR][CIRGen][Builtin][X86] Multishift Intrinsics

Added builtin support for the multishift operation with test file.

changes has been done in CIRGenBuiltinX86 file
---
 clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp      |  7 +++++++
 clang/test/CIR/CodeGen/X86/builtin_multishift.c | 11 +++++++++++
 2 files changed, 18 insertions(+)
 create mode 100644 clang/test/CIR/CodeGen/X86/builtin_multishift.c

diff --git a/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp b/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp
index e7aa8a234efd9..4cbeecf0d8ea3 100644
--- a/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp
@@ -877,9 +877,16 @@ mlir::Value CIRGenFunction::emitX86BuiltinExpr(unsigned builtinID,
   case X86::BI__builtin_ia32_vp2intersect_d_512:
   case X86::BI__builtin_ia32_vp2intersect_d_256:
   case X86::BI__builtin_ia32_vp2intersect_d_128:
+    cgm.errorNYI(expr->getSourceRange(),
+                 std::string("unimplemented X86 builtin call: ") +
+                     getContext().BuiltinInfo.getName(builtinID));
+    return {};
   case X86::BI__builtin_ia32_vpmultishiftqb128:
+    return emitIntrinsicCallOp(*this, expr, "x86_avx512_pmultishift_qb_128", ops[0].getType(), ops);
   case X86::BI__builtin_ia32_vpmultishiftqb256:
+    return emitIntrinsicCallOp(*this, expr, "x86_avx512_pmultishift_qb_256", ops[0].getType(), ops);
   case X86::BI__builtin_ia32_vpmultishiftqb512:
+    return emitIntrinsicCallOp(*this, expr, "x86_avx512_pmultishift_qb_512", ops[0].getType(), ops);
   case X86::BI__builtin_ia32_vpshufbitqmb128_mask:
   case X86::BI__builtin_ia32_vpshufbitqmb256_mask:
   case X86::BI__builtin_ia32_vpshufbitqmb512_mask:
diff --git a/clang/test/CIR/CodeGen/X86/builtin_multishift.c b/clang/test/CIR/CodeGen/X86/builtin_multishift.c
new file mode 100644
index 0000000000000..7c57ef3191d1d
--- /dev/null
+++ b/clang/test/CIR/CodeGen/X86/builtin_multishift.c
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -target-feature +avx512vbmi \
+// RUN:   -fclangir -emit-cir %s -o - | FileCheck %s
+
+#include <immintrin.h>
+__m512i test_multishift(__m512i x, __m512i y) {
+  return _mm512_multishift_epi64_epi8(x, y);
+}
+
+// // CHECK: cir.func @test_multishift
+// // CHECK: cir.call @__builtin_ia32_vpmultishiftqb512
+