[llvm] [RISCV][GISel] Add helper to convert a LLT size to a RegisterBankInfo::ValueMapping* for FP. (PR #71123)

[Craig Topper via llvm-commits]

https://github.com/topperc created https://github.com/llvm/llvm-project/pull/71123

Use this to simplify code.

>From 106f067c3193ff9a446e3cb9d648f9626b00432b Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper at sifive.com>
Date: Thu, 2 Nov 2023 15:17:40 -0700
Subject: [PATCH] [RISCV][GISel] Add helper to convert a LLT size to a
 RegisterBankInfo::ValueMapping* for FP.

Use this to simplify code.
---
 .../RISCV/GISel/RISCVRegisterBankInfo.cpp     | 43 ++++++-------------
 1 file changed, 14 insertions(+), 29 deletions(-)

diff --git a/llvm/lib/Target/RISCV/GISel/RISCVRegisterBankInfo.cpp b/llvm/lib/Target/RISCV/GISel/RISCVRegisterBankInfo.cpp
index f005948d2094445..c50602d54a1a676 100644
--- a/llvm/lib/Target/RISCV/GISel/RISCVRegisterBankInfo.cpp
+++ b/llvm/lib/Target/RISCV/GISel/RISCVRegisterBankInfo.cpp
@@ -66,6 +66,12 @@ enum ValueMappingsIdx {
   FPR32Idx = 7,
   FPR64Idx = 10,
 };
+
+const RegisterBankInfo::ValueMapping *getFPValueMapping(unsigned Size) {
+  assert(Size == 32 || Size == 64);
+  unsigned Idx = Size == 64 ? PMI_FPR64 : PMI_FPR32;
+  return &ValueMappings[1 + Idx * 3];
+}
 } // namespace RISCV
 } // namespace llvm
 
@@ -185,47 +191,26 @@ RISCVRegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
   case TargetOpcode::G_FMAXNUM:
   case TargetOpcode::G_FMINNUM: {
     LLT Ty = MRI.getType(MI.getOperand(0).getReg());
-    OperandsMapping = Ty.getSizeInBits() == 64
-                          ? &RISCV::ValueMappings[RISCV::FPR64Idx]
-                          : &RISCV::ValueMappings[RISCV::FPR32Idx];
+    OperandsMapping = RISCV::getFPValueMapping(Ty.getSizeInBits());
     break;
   }
   case TargetOpcode::G_FMA: {
     LLT Ty = MRI.getType(MI.getOperand(0).getReg());
-    OperandsMapping =
-        Ty.getSizeInBits() == 64
-            ? getOperandsMapping({&RISCV::ValueMappings[RISCV::FPR64Idx],
-                                  &RISCV::ValueMappings[RISCV::FPR64Idx],
-                                  &RISCV::ValueMappings[RISCV::FPR64Idx],
-                                  &RISCV::ValueMappings[RISCV::FPR64Idx]})
-            : getOperandsMapping({&RISCV::ValueMappings[RISCV::FPR32Idx],
-                                  &RISCV::ValueMappings[RISCV::FPR32Idx],
-                                  &RISCV::ValueMappings[RISCV::FPR32Idx],
-                                  &RISCV::ValueMappings[RISCV::FPR32Idx]});
-    break;
-  }
-  case TargetOpcode::G_FPEXT: {
-    LLT ToTy = MRI.getType(MI.getOperand(0).getReg());
-    (void)ToTy;
-    LLT FromTy = MRI.getType(MI.getOperand(1).getReg());
-    (void)FromTy;
-    assert(ToTy.getSizeInBits() == 64 && FromTy.getSizeInBits() == 32 &&
-           "Unsupported size for G_FPEXT");
-    OperandsMapping =
-        getOperandsMapping({&RISCV::ValueMappings[RISCV::FPR64Idx],
-                            &RISCV::ValueMappings[RISCV::FPR32Idx]});
+    const RegisterBankInfo::ValueMapping *FPValueMapping =
+        RISCV::getFPValueMapping(Ty.getSizeInBits());
+    OperandsMapping = getOperandsMapping(
+        {FPValueMapping, FPValueMapping, FPValueMapping, FPValueMapping});
     break;
   }
+  case TargetOpcode::G_FPEXT:
   case TargetOpcode::G_FPTRUNC: {
     LLT ToTy = MRI.getType(MI.getOperand(0).getReg());
     (void)ToTy;
     LLT FromTy = MRI.getType(MI.getOperand(1).getReg());
     (void)FromTy;
-    assert(ToTy.getSizeInBits() == 32 && FromTy.getSizeInBits() == 64 &&
-           "Unsupported size for G_FPTRUNC");
     OperandsMapping =
-        getOperandsMapping({&RISCV::ValueMappings[RISCV::FPR32Idx],
-                            &RISCV::ValueMappings[RISCV::FPR64Idx]});
+        getOperandsMapping({RISCV::getFPValueMapping(ToTy.getSizeInBits()),
+                            RISCV::getFPValueMapping(FromTy.getSizeInBits())});
     break;
   }
   default: