[RISCV] Add areInlineCompatible for riscv target (#86639)

Inline a callee if its target-features are a subset of the callers
target-features.

Author: jacquesguan

llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp

@@ -1676,3 +1676,17 @@ bool RISCVTTIImpl::isLegalMaskedCompressStore(Type *DataTy, Align Alignment) {
     return false;
   return true;
 }
+
+bool RISCVTTIImpl::areInlineCompatible(const Function *Caller,
+                                       const Function *Callee) const {
+  const TargetMachine &TM = getTLI()->getTargetMachine();
+
+  const FeatureBitset &CallerBits =
+      TM.getSubtargetImpl(*Caller)->getFeatureBits();
+  const FeatureBitset &CalleeBits =
+      TM.getSubtargetImpl(*Callee)->getFeatureBits();
+
+  // Inline a callee if its target-features are a subset of the callers
+  // target-features.
+  return (CallerBits & CalleeBits) == CalleeBits;
+}

llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h

@@ -60,6 +60,9 @@ class RISCVTTIImpl : public BasicTTIImplBase<RISCVTTIImpl> {
       : BaseT(TM, F.getParent()->getDataLayout()), ST(TM->getSubtargetImpl(F)),
         TLI(ST->getTargetLowering()) {}
 
+  bool areInlineCompatible(const Function *Caller,
+                           const Function *Callee) const;
+
   /// Return the cost of materializing an immediate for a value operand of
   /// a store instruction.
   InstructionCost getStoreImmCost(Type *VecTy, TTI::OperandValueInfo OpInfo,

llvm/test/Transforms/Inline/RISCV/inline-target-features.ll

@@ -0,0 +1,34 @@
+; RUN: opt < %s -mtriple=riscv64-unknown-linux-gnu -S -passes=inline | FileCheck %s
+; RUN: opt < %s -mtriple=riscv64-unknown-linux-gnu -S -passes='cgscc(inline)' | FileCheck %s
+; Check that we only inline when we have compatible target attributes.
+
+target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n64-S128"
+target triple = "riscv64-unknown-linux-gnu"
+
+define i32 @foo() #0 {
+entry:
+  %call = call i32 (...) @baz()
+  ret i32 %call
+; CHECK-LABEL: foo
+; CHECK: call i32 (...) @baz()
+}
+declare i32 @baz(...) #0
+
+define i32 @bar() #1 {
+entry:
+  %call = call i32 @foo()
+  ret i32 %call
+; CHECK-LABEL: bar
+; CHECK: call i32 (...) @baz()
+}
+
+define i32 @qux() #0 {
+entry:
+  %call = call i32 @bar()
+  ret i32 %call
+; CHECK-LABEL: qux
+; CHECK: call i32 @bar()
+}
+
+attributes #0 = { "target-cpu"="generic-rv64" "target-features"="+f,+d" }
+attributes #1 = { "target-cpu"="generic-rv64" "target-features"="+f,+d,+m,+v" }

llvm/test/Transforms/Inline/RISCV/lit.local.cfg

@@ -0,0 +1,2 @@
+if not "RISCV" in config.root.targets:
+    config.unsupported = True