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

[Jianjian Guan via llvm-commits]

https://github.com/jacquesguan created https://github.com/llvm/llvm-project/pull/86639

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

>From 8fc151691d1e78492fc8aeb1136fdce30459e94a Mon Sep 17 00:00:00 2001
From: Jianjian GUAN <jacquesguan at me.com>
Date: Tue, 26 Mar 2024 15:39:07 +0800
Subject: [PATCH] [RISCV] Add areInlineCompatible for riscv target

Inline a callee if its target-features are a subset of the callers target-features.
---
 .../Target/RISCV/RISCVTargetTransformInfo.cpp | 14 ++++++++
 .../Target/RISCV/RISCVTargetTransformInfo.h   |  3 ++
 .../Inline/RISCV/inline-target-features.ll    | 34 +++++++++++++++++++
 .../Transforms/Inline/RISCV/lit.local.cfg     |  2 ++
 4 files changed, 53 insertions(+)
 create mode 100644 llvm/test/Transforms/Inline/RISCV/inline-target-features.ll
 create mode 100644 llvm/test/Transforms/Inline/RISCV/lit.local.cfg

diff --git a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
index f75b3d3caa62f2..b8f3c13e4508b0 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
+++ b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
@@ -1675,3 +1675,17 @@ 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;
+}
diff --git a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h
index 8daf6845dc8bc9..ac32aea4ce2b8f 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h
+++ b/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,
diff --git a/llvm/test/Transforms/Inline/RISCV/inline-target-features.ll b/llvm/test/Transforms/Inline/RISCV/inline-target-features.ll
new file mode 100644
index 00000000000000..b626a229a737d5
--- /dev/null
+++ b/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" }
diff --git a/llvm/test/Transforms/Inline/RISCV/lit.local.cfg b/llvm/test/Transforms/Inline/RISCV/lit.local.cfg
new file mode 100644
index 00000000000000..17351748513d98
--- /dev/null
+++ b/llvm/test/Transforms/Inline/RISCV/lit.local.cfg
@@ -0,0 +1,2 @@
+if not "RISCV" in config.root.targets:
+    config.unsupported = True