[llvm] [RISCV][NFC] Add helpers for RVV register classes (PR #84144)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-risc-v

Author: Wang Pengcheng (wangpc-pp)

<details>
<summary>Changes</summary>

There are two places in tree that use these helpers and there will
be more future usages.


---
Full diff: https://github.com/llvm/llvm-project/pull/84144.diff


2 Files Affected:

- (modified) llvm/lib/Target/RISCV/RISCVRegisterInfo.h (+20-2) 
- (modified) llvm/lib/Target/RISCV/RISCVTargetMachine.cpp (+3-15) 


``````````diff
diff --git a/llvm/lib/Target/RISCV/RISCVRegisterInfo.h b/llvm/lib/Target/RISCV/RISCVRegisterInfo.h
index e46fe8ecb900fc..f5b4cac7dffd74 100644
--- a/llvm/lib/Target/RISCV/RISCVRegisterInfo.h
+++ b/llvm/lib/Target/RISCV/RISCVRegisterInfo.h
@@ -110,13 +110,31 @@ struct RISCVRegisterInfo : public RISCVGenRegisterInfo {
     return RC;
   }
 
-  bool doesRegClassHavePseudoInitUndef(
-      const TargetRegisterClass *RC) const override {
+  bool isRVVRegClass(const TargetRegisterClass *RC) const {
     return RISCV::VRRegClass.hasSubClassEq(RC) ||
            RISCV::VRM2RegClass.hasSubClassEq(RC) ||
            RISCV::VRM4RegClass.hasSubClassEq(RC) ||
            RISCV::VRM8RegClass.hasSubClassEq(RC);
   }
+
+  bool isRVVSegmentRegClass(const TargetRegisterClass *RC) const {
+    return RISCV::VRN2M1RegClass.hasSubClassEq(RC) ||
+           RISCV::VRN2M2RegClass.hasSubClassEq(RC) ||
+           RISCV::VRN2M4RegClass.hasSubClassEq(RC) ||
+           RISCV::VRN3M1RegClass.hasSubClassEq(RC) ||
+           RISCV::VRN3M2RegClass.hasSubClassEq(RC) ||
+           RISCV::VRN4M1RegClass.hasSubClassEq(RC) ||
+           RISCV::VRN4M2RegClass.hasSubClassEq(RC) ||
+           RISCV::VRN5M1RegClass.hasSubClassEq(RC) ||
+           RISCV::VRN6M1RegClass.hasSubClassEq(RC) ||
+           RISCV::VRN7M1RegClass.hasSubClassEq(RC) ||
+           RISCV::VRN8M1RegClass.hasSubClassEq(RC);
+  }
+
+  bool doesRegClassHavePseudoInitUndef(
+      const TargetRegisterClass *RC) const override {
+    return isRVVRegClass(RC);
+  }
 };
 }
 
diff --git a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp b/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
index 6fe0abaccb9d98..e499f77fb7772b 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
+++ b/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
@@ -14,6 +14,7 @@
 #include "MCTargetDesc/RISCVBaseInfo.h"
 #include "RISCV.h"
 #include "RISCVMachineFunctionInfo.h"
+#include "RISCVRegisterInfo.h"
 #include "RISCVTargetObjectFile.h"
 #include "RISCVTargetTransformInfo.h"
 #include "TargetInfo/RISCVTargetInfo.h"
@@ -278,21 +279,8 @@ class RVVRegisterRegAlloc : public RegisterRegAllocBase<RVVRegisterRegAlloc> {
 
 static bool onlyAllocateRVVReg(const TargetRegisterInfo &TRI,
                                const TargetRegisterClass &RC) {
-  return RISCV::VRRegClass.hasSubClassEq(&RC) ||
-         RISCV::VRM2RegClass.hasSubClassEq(&RC) ||
-         RISCV::VRM4RegClass.hasSubClassEq(&RC) ||
-         RISCV::VRM8RegClass.hasSubClassEq(&RC) ||
-         RISCV::VRN2M1RegClass.hasSubClassEq(&RC) ||
-         RISCV::VRN2M2RegClass.hasSubClassEq(&RC) ||
-         RISCV::VRN2M4RegClass.hasSubClassEq(&RC) ||
-         RISCV::VRN3M1RegClass.hasSubClassEq(&RC) ||
-         RISCV::VRN3M2RegClass.hasSubClassEq(&RC) ||
-         RISCV::VRN4M1RegClass.hasSubClassEq(&RC) ||
-         RISCV::VRN4M2RegClass.hasSubClassEq(&RC) ||
-         RISCV::VRN5M1RegClass.hasSubClassEq(&RC) ||
-         RISCV::VRN6M1RegClass.hasSubClassEq(&RC) ||
-         RISCV::VRN7M1RegClass.hasSubClassEq(&RC) ||
-         RISCV::VRN8M1RegClass.hasSubClassEq(&RC);
+  auto &RegInfo = static_cast<const RISCVRegisterInfo &>(TRI);
+  return RegInfo.isRVVRegClass(&RC) || RegInfo.isRVVSegmentRegClass(&RC);
 }
 
 static FunctionPass *useDefaultRegisterAllocator() { return nullptr; }

``````````

</details>


https://github.com/llvm/llvm-project/pull/84144