[Attributor] Restrict liveness and return information to functions

Summary:
Until we have proper call-site information we should not recompute
liveness and return information for each call site. This patch directly
uses the function versions and introduces TODOs at the usage sites.

The required iterations to get to the fixpoint are most of the time
reduced by this change and we always avoid work duplication.

Reviewers: sstefan1, uenoku

Subscribers: hiraditya, bollu, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66562

llvm-svn: 370208

8 files changed, 69 insertions, 21 deletions

diff --git a/llvm/lib/Transforms/IPO/Attributor.cpp b/llvm/lib/Transforms/IPO/Attributor.cpp
index a2d470affc0..d441012000e 100644
--- a/llvm/lib/Transforms/IPO/Attributor.cpp
+++ b/llvm/lib/Transforms/IPO/Attributor.cpp
@@ -971,8 +971,16 @@ ChangeStatus AAReturnedValuesImpl::updateImpl(Attributor &A) {
     if (!CB || UnresolvedCalls.count(CB))
       continue;
 
-    const auto &RetValAA =
-        A.getAAFor<AAReturnedValues>(*this, IRPosition::callsite_function(*CB));
+    if (!CB->getCalledFunction()) {
+      LLVM_DEBUG(dbgs() << "[AAReturnedValues] Unresolved call: " << *CB
+                        << "\n");
+      UnresolvedCalls.insert(CB);
+      continue;
+    }
+
+    // TODO: use the function scope once we have call site AAReturnedValues.
+    const auto &RetValAA = A.getAAFor<AAReturnedValues>(
+        *this, IRPosition::function(*CB->getCalledFunction()));
     LLVM_DEBUG(dbgs() << "[AAReturnedValues] Found another AAReturnedValues: "
                       << static_cast<const AbstractAttribute &>(RetValAA)
                       << "\n");
@@ -1070,7 +1078,27 @@ struct AAReturnedValuesFunction final : public AAReturnedValuesImpl {
 };
 
 /// Returned values information for a call sites.
-using AAReturnedValuesCallSite = AAReturnedValuesFunction;
+struct AAReturnedValuesCallSite final : AAReturnedValuesImpl {
+  AAReturnedValuesCallSite(const IRPosition &IRP) : AAReturnedValuesImpl(IRP) {}
+
+  /// See AbstractAttribute::initialize(...).
+  void initialize(Attributor &A) override {
+    // TODO: Once we have call site specific value information we can provide
+    //       call site specific liveness liveness information and then it makes
+    //       sense to specialize attributes for call sites instead of
+    //       redirecting requests to the callee.
+    llvm_unreachable("Abstract attributes for returned values are not "
+                     "supported for call sites yet!");
+  }
+
+  /// See AbstractAttribute::updateImpl(...).
+  ChangeStatus updateImpl(Attributor &A) override {
+    return indicatePessimisticFixpoint();
+  }
+
+  /// See AbstractAttribute::trackStatistics()
+  void trackStatistics() const override {}
+};
 
 /// ------------------------ NoSync Function Attribute -------------------------
 
@@ -1929,12 +1957,27 @@ ChangeStatus AAIsDeadImpl::updateImpl(Attributor &A) {
 }
 
 /// Liveness information for a call sites.
-//
-// TODO: Once we have call site specific value information we can provide call
-//       site specific liveness liveness information and then it makes sense to
-//       specialize attributes for call sites instead of redirecting requests to
-//       the callee.
-using AAIsDeadCallSite = AAIsDeadFunction;
+struct AAIsDeadCallSite final : AAIsDeadImpl {
+  AAIsDeadCallSite(const IRPosition &IRP) : AAIsDeadImpl(IRP) {}
+
+  /// See AbstractAttribute::initialize(...).
+  void initialize(Attributor &A) override {
+    // TODO: Once we have call site specific value information we can provide
+    //       call site specific liveness liveness information and then it makes
+    //       sense to specialize attributes for call sites instead of
+    //       redirecting requests to the callee.
+    llvm_unreachable("Abstract attributes for liveness are not "
+                     "supported for call sites yet!");
+  }
+
+  /// See AbstractAttribute::updateImpl(...).
+  ChangeStatus updateImpl(Attributor &A) override {
+    return indicatePessimisticFixpoint();
+  }
+
+  /// See AbstractAttribute::trackStatistics()
+  void trackStatistics() const override {}
+};
 
 /// -------------------- Dereferenceable Argument Attribute --------------------
 
@@ -2385,7 +2428,8 @@ bool Attributor::checkForAllReturnedValuesAndReturnInsts(
 
   // If this is a call site query we use the call site specific return values
   // and liveness information.
-  const IRPosition &QueryIRP = IRPosition::function_scope(IRP);
+  // TODO: use the function scope once we have call site AAReturnedValues.
+  const IRPosition &QueryIRP = IRPosition::function(*AssociatedFunction);
   const auto &AARetVal = getAAFor<AAReturnedValues>(QueryingAA, QueryIRP);
   if (!AARetVal.getState().isValidState())
     return false;
@@ -2402,7 +2446,8 @@ bool Attributor::checkForAllReturnedValues(
   if (!AssociatedFunction || !AssociatedFunction->hasExactDefinition())
     return false;
 
-  const IRPosition &QueryIRP = IRPosition::function_scope(IRP);
+  // TODO: use the function scope once we have call site AAReturnedValues.
+  const IRPosition &QueryIRP = IRPosition::function(*AssociatedFunction);
   const auto &AARetVal = getAAFor<AAReturnedValues>(QueryingAA, QueryIRP);
   if (!AARetVal.getState().isValidState())
     return false;
@@ -2423,7 +2468,8 @@ bool Attributor::checkForAllInstructions(
   if (!AssociatedFunction || !AssociatedFunction->hasExactDefinition())
     return false;
 
-  const IRPosition &QueryIRP = IRPosition::function_scope(IRP);
+  // TODO: use the function scope once we have call site AAReturnedValues.
+  const IRPosition &QueryIRP = IRPosition::function(*AssociatedFunction);
   const auto &LivenessAA =
       getAAFor<AAIsDead>(QueryingAA, QueryIRP, /* TrackDependence */ false);
   bool AnyDead = false;
@@ -2459,8 +2505,10 @@ bool Attributor::checkForAllReadWriteInstructions(
   if (!AssociatedFunction)
     return false;
 
-  const auto &LivenessAA = getAAFor<AAIsDead>(
-      QueryingAA, QueryingAA.getIRPosition(), /* TrackDependence */ false);
+  // TODO: use the function scope once we have call site AAReturnedValues.
+  const IRPosition &QueryIRP = IRPosition::function(*AssociatedFunction);
+  const auto &LivenessAA =
+      getAAFor<AAIsDead>(QueryingAA, QueryIRP, /* TrackDependence */ false);
   bool AnyDead = false;
 
   for (Instruction *I :
diff --git a/llvm/test/Transforms/FunctionAttrs/align.ll b/llvm/test/Transforms/FunctionAttrs/align.ll
index 0531ca729d9..fd387911386 100644
--- a/llvm/test/Transforms/FunctionAttrs/align.ll
+++ b/llvm/test/Transforms/FunctionAttrs/align.ll
@@ -1,4 +1,4 @@
-; RUN: opt -attributor -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=17 -S < %s | FileCheck %s --check-prefix=ATTRIBUTOR
+; RUN: opt -attributor -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=15 -S < %s | FileCheck %s --check-prefix=ATTRIBUTOR
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 
diff --git a/llvm/test/Transforms/FunctionAttrs/arg_nocapture.ll b/llvm/test/Transforms/FunctionAttrs/arg_nocapture.ll
index ffa0fe5d346..5905575c820 100644
--- a/llvm/test/Transforms/FunctionAttrs/arg_nocapture.ll
+++ b/llvm/test/Transforms/FunctionAttrs/arg_nocapture.ll
@@ -1,4 +1,4 @@
-; RUN: opt -functionattrs -attributor -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=18 -S < %s | FileCheck %s
+; RUN: opt -functionattrs -attributor -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=16 -S < %s | FileCheck %s
 ;
 ; Test cases specifically designed for the "no-capture" argument attribute.
 ; We use FIXME's to indicate problems and missing attributes.
diff --git a/llvm/test/Transforms/FunctionAttrs/arg_returned.ll b/llvm/test/Transforms/FunctionAttrs/arg_returned.ll
index 9ea95e20ca1..9a4cc4d68ec 100644
--- a/llvm/test/Transforms/FunctionAttrs/arg_returned.ll
+++ b/llvm/test/Transforms/FunctionAttrs/arg_returned.ll
@@ -1,5 +1,5 @@
 ; RUN: opt -functionattrs -S < %s | FileCheck %s --check-prefix=FNATTR
-; RUN: opt -attributor -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=26 -S < %s | FileCheck %s --check-prefix=ATTRIBUTOR
+; RUN: opt -attributor -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=22 -S < %s | FileCheck %s --check-prefix=ATTRIBUTOR
 ; RUN: opt -attributor -attributor-disable=false -functionattrs -S < %s | FileCheck %s --check-prefix=BOTH
 ;
 ; Test cases specifically designed for the "returned" argument attribute.
diff --git a/llvm/test/Transforms/FunctionAttrs/liveness.ll b/llvm/test/Transforms/FunctionAttrs/liveness.ll
index 54bb9eac628..7dc392c674d 100644
--- a/llvm/test/Transforms/FunctionAttrs/liveness.ll
+++ b/llvm/test/Transforms/FunctionAttrs/liveness.ll
@@ -1,4 +1,4 @@
-; RUN: opt -attributor --attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=6 -S < %s | FileCheck %s
+; RUN: opt -attributor --attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=7 -S < %s | FileCheck %s
 
 declare void @no_return_call() nofree noreturn nounwind readnone
 
diff --git a/llvm/test/Transforms/FunctionAttrs/nonnull.ll b/llvm/test/Transforms/FunctionAttrs/nonnull.ll
index 1022b7c5437..e7fbb9194d3 100644
--- a/llvm/test/Transforms/FunctionAttrs/nonnull.ll
+++ b/llvm/test/Transforms/FunctionAttrs/nonnull.ll
@@ -1,6 +1,6 @@
 ; RUN: opt -S -functionattrs -enable-nonnull-arg-prop %s | FileCheck %s --check-prefixes=BOTH,FNATTR
 ; RUN: opt -S -passes=function-attrs -enable-nonnull-arg-prop %s | FileCheck %s --check-prefixes=BOTH,FNATTR
-; RUN: opt -attributor --attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=12 -S < %s | FileCheck %s --check-prefixes=BOTH,ATTRIBUTOR
+; RUN: opt -attributor --attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=11 -S < %s | FileCheck %s --check-prefixes=BOTH,ATTRIBUTOR
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 
diff --git a/llvm/test/Transforms/FunctionAttrs/nounwind.ll b/llvm/test/Transforms/FunctionAttrs/nounwind.ll
index 66f23598b4e..c2c30f0fe38 100644
--- a/llvm/test/Transforms/FunctionAttrs/nounwind.ll
+++ b/llvm/test/Transforms/FunctionAttrs/nounwind.ll
@@ -1,5 +1,5 @@
 ; RUN: opt < %s -functionattrs -S | FileCheck %s
-; RUN: opt < %s -attributor -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=12 -S | FileCheck %s --check-prefix=ATTRIBUTOR
+; RUN: opt < %s -attributor -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=10 -S | FileCheck %s --check-prefix=ATTRIBUTOR
 
 ; TEST 1
 ; CHECK: Function Attrs: norecurse nounwind readnone
diff --git a/llvm/test/Transforms/FunctionAttrs/read_write_returned_arguments_scc.ll b/llvm/test/Transforms/FunctionAttrs/read_write_returned_arguments_scc.ll
index ed16ac8fcbf..d95dd2d028d 100644
--- a/llvm/test/Transforms/FunctionAttrs/read_write_returned_arguments_scc.ll
+++ b/llvm/test/Transforms/FunctionAttrs/read_write_returned_arguments_scc.ll
@@ -1,4 +1,4 @@
-; RUN: opt -functionattrs -enable-nonnull-arg-prop -attributor -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=28 -S < %s | FileCheck %s
+; RUN: opt -functionattrs -enable-nonnull-arg-prop -attributor -attributor-disable=false -attributor-max-iterations-verify -attributor-max-iterations=21 -S < %s | FileCheck %s
 ;
 ; This is an evolved example to stress test SCC parameter attribute propagation.
 ; The SCC in this test is made up of the following six function, three of which