[PATCH] D127899: [MLInliner] Don't inline call sites in unreachable basic blocks

[Mircea Trofin via Phabricator via llvm-commits]

mtrofin updated this revision to Diff 437563.
mtrofin marked 2 inline comments as done.
mtrofin added a comment.

feedback


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D127899/new/

https://reviews.llvm.org/D127899

Files:
  llvm/include/llvm/Analysis/MLInlineAdvisor.h
  llvm/lib/Analysis/MLInlineAdvisor.cpp
  llvm/test/Transforms/Inline/ML/skip-unreachable.ll


Index: llvm/test/Transforms/Inline/ML/skip-unreachable.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/Inline/ML/skip-unreachable.ll
@@ -0,0 +1,46 @@
+; Test skipping inlining when the callsite is unreachable (for both mandatory
+; and non-mandatory cases)
+; REQUIRES: llvm_inliner_model_autogenerated
+; RUN: opt -passes=inliner-ml-advisor-release -S < %s | FileCheck %s --check-prefix=CHECK
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-grtev4-linux-gnu"
+
+; Mandatory case
+define i32 @f1() {
+entry:
+  br label %exit
+some_bb:  ; unreachable - has no predecessors
+  %r = call i32 @f2()
+  br label %exit
+exit:
+  ret i32 1
+}
+
+define i32 @f2() #0 {
+  ret i32 2
+}
+
+; Non-mandatory case
+define i32 @f3() {
+entry:
+  br label %exit
+some_bb:  ; unreachable - has no predecessors
+  %r = call i32 @f4()
+  br label %exit
+exit:
+  ret i32 1
+}
+
+define i32 @f4() {
+  ret i32 2
+}
+
+attributes #0 = { alwaysinline }
+
+; CHECK-LABEL: @f1
+; CHECK-LABEL: some_bb
+; CHECK-NEXT: call i32 @f2
+; CHECK-LABEL: @f3
+; CHECK-LABEL: some_bb
+; CHECK-NEXT: call i32 @f4
Index: llvm/lib/Analysis/MLInlineAdvisor.cpp
===================================================================
--- llvm/lib/Analysis/MLInlineAdvisor.cpp
+++ llvm/lib/Analysis/MLInlineAdvisor.cpp
@@ -277,6 +277,9 @@
 }
 
 std::unique_ptr<InlineAdvice> MLInlineAdvisor::getAdviceImpl(CallBase &CB) {
+  if (auto Skip = getSkipAdviceIfUnreachableCallsite(CB))
+    return Skip;
+
   auto &Caller = *CB.getCaller();
   auto &Callee = *CB.getCalledFunction();
 
@@ -376,9 +379,19 @@
       this, CB, ORE, static_cast<bool>(ModelRunner->evaluate<int64_t>()));
 }
 
+std::unique_ptr<InlineAdvice>
+MLInlineAdvisor::getSkipAdviceIfUnreachableCallsite(CallBase &CB) {
+  if (!FAM.getResult<DominatorTreeAnalysis>(*CB.getCaller())
+           .isReachableFromEntry(CB.getParent()))
+    return std::make_unique<InlineAdvice>(this, CB, getCallerORE(CB), false);
+  return nullptr;
+}
+
 std::unique_ptr<InlineAdvice> MLInlineAdvisor::getMandatoryAdvice(CallBase &CB,
                                                                   bool Advice) {
   // Make sure we track inlinings in all cases - mandatory or not.
+  if (auto Skip = getSkipAdviceIfUnreachableCallsite(CB))
+    return Skip;
   if (Advice && !ForceStop)
     return getMandatoryAdviceImpl(CB);
 
Index: llvm/include/llvm/Analysis/MLInlineAdvisor.h
===================================================================
--- llvm/include/llvm/Analysis/MLInlineAdvisor.h
+++ llvm/include/llvm/Analysis/MLInlineAdvisor.h
@@ -65,7 +65,8 @@
 
 private:
   int64_t getModuleIRSize() const;
-
+  std::unique_ptr<InlineAdvice>
+  getSkipAdviceIfUnreachableCallsite(CallBase &CB);
   void print(raw_ostream &OS) const override;
 
   mutable DenseMap<const Function *, FunctionPropertiesInfo> FPICache;


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