[llvm-branch-commits] [llvm] [CodeGen][StaticDataSplitter]Support constant pool partitioning (PR #129781)

[Wei Xiao via llvm-branch-commits]

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@@ -112,21 +117,52 @@ bool StaticDataSplitter::runOnMachineFunction(MachineFunction &MF) {
   return Changed;
 }
 
+const Constant *
+StaticDataSplitter::getConstant(const MachineOperand &Op,
+                                const TargetMachine &TM,
+                                const MachineConstantPool *MCP) {
+  if (!Op.isGlobal() && !Op.isCPI())
+    return nullptr;
+
+  if (Op.isGlobal()) {
+    // Find global variables with local linkage.
+    const GlobalVariable *GV = getLocalLinkageGlobalVariable(Op.getGlobal());
+    // Skip 'special' global variables conservatively because they are
+    // often handled specially, and skip those not in static data
+    // sections.
+    if (!GV || GV->getName().starts_with("llvm.") ||
+        !inStaticDataSection(GV, TM))
+      return nullptr;
+    return GV;
+  }
+  assert(Op.isCPI() && "Op must be constant pool index in this branch");
+  int CPI = Op.getIndex();
+  if (CPI == -1)
+    return nullptr;
+
+  assert(MCP != nullptr && "Constant pool info is not available.");
+  const MachineConstantPoolEntry &CPE = MCP->getConstants()[CPI];
+
+  if (CPE.isMachineConstantPoolEntry())
+    return nullptr;
+
+  return CPE.Val.ConstVal;
+}
+
 bool StaticDataSplitter::partitionStaticDataWithProfiles(MachineFunction &MF) {
   int NumChangedJumpTables = 0;
 
-  const TargetMachine &TM = MF.getTarget();
   MachineJumpTableInfo *MJTI = MF.getJumpTableInfo();
 
   // Jump table could be used by either terminating instructions or
   // non-terminating ones, so we walk all instructions and use
   // `MachineOperand::isJTI()` to identify jump table operands.
-  // Similarly, `MachineOperand::isCPI()` can identify constant pool usages
-  // in the same loop.
+  // Similarly, `MachineOperand::isCPI()` is used to identify constant pool
+  // usages in the same loop.
   for (const auto &MBB : MF) {
     for (const MachineInstr &I : MBB) {
       for (const MachineOperand &Op : I.operands()) {
-        if (!Op.isJTI() && !Op.isGlobal())
+        if (!Op.isJTI() && !Op.isGlobal() && !Op.isCPI())
           continue;
 
         std::optional<uint64_t> Count = MBFI->getBlockProfileCount(&MBB);
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williamweixiao wrote:

line 168 can be hoisted out to the outmost loop (i.e line 163).

https://github.com/llvm/llvm-project/pull/129781