[clang] [llvm] [X86] Remove USER_MSR from DMR (PR #164232)

[Mikołaj Piróg via llvm-commits]

https://github.com/mikolaj-pirog created https://github.com/llvm/llvm-project/pull/164232

Per Intel Architecture Instruction Set Extensions Programming Reference rev. 59 (https://cdrdv2.intel.com/v1/dl/getContent/671368), table 1-2, DMR doesn't support USER_MSR (URDMSR and UWRMSR instructions)


>From c949cbb4af6ade342e0be7565c81ecd6bf492a10 Mon Sep 17 00:00:00 2001
From: "Pirog, Mikolaj Maciej" <mikolaj.maciej.pirog at intel.com>
Date: Mon, 20 Oct 2025 12:39:11 +0200
Subject: [PATCH] Remove USER_MSR from DMR

---
 clang/test/Preprocessor/predefined-arch-macros.c | 2 --
 llvm/lib/Target/X86/X86.td                       | 1 -
 llvm/lib/TargetParser/X86TargetParser.cpp        | 2 +-
 3 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/clang/test/Preprocessor/predefined-arch-macros.c b/clang/test/Preprocessor/predefined-arch-macros.c
index e2f4bcbfd2382..9f24147f707ce 100644
--- a/clang/test/Preprocessor/predefined-arch-macros.c
+++ b/clang/test/Preprocessor/predefined-arch-macros.c
@@ -1911,7 +1911,6 @@
 // CHECK_GNR_M32: #define __TSXLDTRK__ 1
 // CHECK_GNR_M32: #define __UINTR__ 1
 // CHECK_GNR_M32-NOT: #define __USERMSR__ 1
-// CHECK_DMR_M32: #define __USERMSR__ 1
 // CHECK_GNR_M32: #define __VAES__ 1
 // CHECK_GNR_M32: #define __VPCLMULQDQ__ 1
 // CHECK_GNR_M32: #define __WAITPKG__ 1
@@ -2018,7 +2017,6 @@
 // CHECK_GNR_M64: #define __TSXLDTRK__ 1
 // CHECK_GNR_M64: #define __UINTR__ 1
 // CHECK_GNR_M64-NOT: #define __USERMSR__ 1
-// CHECK_DMR_M64: #define __USERMSR__ 1
 // CHECK_GNR_M64: #define __VAES__ 1
 // CHECK_GNR_M64: #define __VPCLMULQDQ__ 1
 // CHECK_GNR_M64: #define __WAITPKG__ 1
diff --git a/llvm/lib/Target/X86/X86.td b/llvm/lib/Target/X86/X86.td
index 6db780f91f3b9..74e67caf52b02 100644
--- a/llvm/lib/Target/X86/X86.td
+++ b/llvm/lib/Target/X86/X86.td
@@ -1164,7 +1164,6 @@ def ProcessorFeatures {
                                                   FeatureAVXNECONVERT,
                                                   FeatureAVXVNNIINT8,
                                                   FeatureAVXVNNIINT16,
-                                                  FeatureUSERMSR,
                                                   FeatureSHA512,
                                                   FeatureSM3,
                                                   FeatureEGPR,
diff --git a/llvm/lib/TargetParser/X86TargetParser.cpp b/llvm/lib/TargetParser/X86TargetParser.cpp
index e382cfe9d14fe..43d3a65e8191d 100644
--- a/llvm/lib/TargetParser/X86TargetParser.cpp
+++ b/llvm/lib/TargetParser/X86TargetParser.cpp
@@ -144,7 +144,7 @@ constexpr FeatureBitset FeaturesDiamondRapids =
     FeatureSM4 | FeatureEGPR | FeatureZU | FeatureCCMP | FeaturePush2Pop2 |
     FeaturePPX | FeatureNDD | FeatureNF | FeatureMOVRS | FeatureAMX_MOVRS |
     FeatureAMX_AVX512 | FeatureAMX_FP8 | FeatureAMX_TF32 |
-    FeatureAMX_TRANSPOSE | FeatureUSERMSR;
+    FeatureAMX_TRANSPOSE;
 
 // Intel Atom processors.
 // Bonnell has feature parity with Core2 and adds MOVBE.