[llvm] Implement areInlineCompatible for SystemZ using feature bitset (PR #132976)

[Andres Chavarria via llvm-commits]

https://github.com/chavandres updated https://github.com/llvm/llvm-project/pull/132976

>From 99f11074bf20079330d0f209fbc55ce042a7ff95 Mon Sep 17 00:00:00 2001
From: Andres Chavarria <adrchb24 at gmail.com>
Date: Tue, 18 Mar 2025 19:52:38 -0600
Subject: [PATCH] [SystemZ] Implement areInlineCompatible for SystemZ TTI

---
 .../SystemZ/SystemZTargetTransformInfo.cpp    | 14 +++++++
 .../SystemZ/SystemZTargetTransformInfo.h      |  4 ++
 .../Inline/SystemZ/inline-target-attr.ll      | 42 +++++++++++++++++++
 .../Transforms/Inline/SystemZ/lit.local.cfg   |  2 +
 4 files changed, 62 insertions(+)
 create mode 100644 llvm/test/Transforms/Inline/SystemZ/inline-target-attr.ll
 create mode 100644 llvm/test/Transforms/Inline/SystemZ/lit.local.cfg

diff --git a/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp b/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
index 06a0a3a631654..e0b0099466c52 100644
--- a/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
@@ -422,6 +422,20 @@ bool SystemZTTIImpl::isLSRCostLess(const TargetTransformInfo::LSRCost &C1,
              C2.ScaleCost, C2.SetupCost);
 }
 
+bool SystemZTTIImpl::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();
+
+  // Support only equal feature bitsets. Restriction should be relaxed in the
+  // future to allow inlining when callee's bits are subset of the caller's.
+  return CallerBits == CalleeBits;
+}
+
 unsigned SystemZTTIImpl::getNumberOfRegisters(unsigned ClassID) const {
   bool Vector = (ClassID == 1);
   if (!Vector)
diff --git a/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.h b/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.h
index 512fcc854d532..e64b1f1ccbd93 100644
--- a/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.h
+++ b/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.h
@@ -62,6 +62,10 @@ class SystemZTTIImpl : public BasicTTIImplBase<SystemZTTIImpl> {
 
   bool isLSRCostLess(const TargetTransformInfo::LSRCost &C1,
                      const TargetTransformInfo::LSRCost &C2);
+
+  bool areInlineCompatible(const Function *Caller,
+                           const Function *Callee) const;
+
   /// @}
 
   /// \name Vector TTI Implementations
diff --git a/llvm/test/Transforms/Inline/SystemZ/inline-target-attr.ll b/llvm/test/Transforms/Inline/SystemZ/inline-target-attr.ll
new file mode 100644
index 0000000000000..b5c4f42655bb4
--- /dev/null
+++ b/llvm/test/Transforms/Inline/SystemZ/inline-target-attr.ll
@@ -0,0 +1,42 @@
+; RUN: opt < %s -mtriple=s390x-linux-gnu -S -passes=inline | FileCheck %s
+; RUN: opt < %s -mtriple=s390x-linux-gnu -S -passes='cgscc(inline)' | FileCheck %s
+; Check that we only inline when we have equal target attributes.
+
+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 @foo()
+}
+
+define i32 @qux() #0 {
+entry:
+  %call = call i32 @foo()
+  ret i32 %call
+; CHECK-LABEL: qux
+; CHECK: call i32 (...) @baz()
+}
+
+define i32 @quux() #2 {
+entry:
+  %call = call i32 @bar()
+  ret i32 %call
+; CHECK-LABEL: quux
+; CHECK: call i32 @bar()
+}
+
+
+attributes #0 = { "target-cpu"="generic" "target-features"="+guarded-storage" }
+attributes #1 = { "target-cpu"="generic" "target-features"="+guarded-storage,+enhanced-sort" }
+attributes #2 = { "target-cpu"="generic" "target-features"="+concurrent-functions" }
diff --git a/llvm/test/Transforms/Inline/SystemZ/lit.local.cfg b/llvm/test/Transforms/Inline/SystemZ/lit.local.cfg
new file mode 100644
index 0000000000000..f9dd98a21cc3e
--- /dev/null
+++ b/llvm/test/Transforms/Inline/SystemZ/lit.local.cfg
@@ -0,0 +1,2 @@
+if not "SystemZ" in config.root.targets:
+    config.unsupported = True