[llvm] 214ed3f - [Attributor] Record dependences only when necessary

[Johannes Doerfert via llvm-commits]

Author: Johannes Doerfert
Date: 2020-01-23T18:42:45-06:00
New Revision: 214ed3f676d2a1f0329c8dd4b3a0d4218f2b96cb

URL: https://github.com/llvm/llvm-project/commit/214ed3f676d2a1f0329c8dd4b3a0d4218f2b96cb
DIFF: https://github.com/llvm/llvm-project/commit/214ed3f676d2a1f0329c8dd4b3a0d4218f2b96cb.diff

LOG: [Attributor] Record dependences only when necessary

If we use assumed information from AAValueSimplify we need to record
an OPTIONAL dependence, otherwise we do not.

Added: 
    

Modified: 
    llvm/lib/Transforms/IPO/Attributor.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/IPO/Attributor.cpp b/llvm/lib/Transforms/IPO/Attributor.cpp
index 648dc8f2ba18..a7e9c5ddaa16 100644
--- a/llvm/lib/Transforms/IPO/Attributor.cpp
+++ b/llvm/lib/Transforms/IPO/Attributor.cpp
@@ -255,6 +255,28 @@ static void replaceAllInstructionUsesWith(Value &Old, Value &New) {
     U->set(&New);
 }
 
+static Optional<ConstantInt *>
+getAssumedConstant(Attributor &A, const Value &V, const AbstractAttribute &AA,
+                   bool &UsedAssumedInformation) {
+  const auto &ValueSimplifyAA = A.getAAFor<AAValueSimplify>(
+      AA, IRPosition::value(V), /* TrackDependence */ false);
+  Optional<Value *> SimplifiedV = ValueSimplifyAA.getAssumedSimplifiedValue(A);
+  bool IsKnown = ValueSimplifyAA.isKnown();
+  UsedAssumedInformation |= !IsKnown;
+  if (!SimplifiedV.hasValue()) {
+    A.recordDependence(ValueSimplifyAA, AA, DepClassTy::OPTIONAL);
+    return llvm::None;
+  }
+  if (isa_and_nonnull<UndefValue>(SimplifiedV.getValue())) {
+    A.recordDependence(ValueSimplifyAA, AA, DepClassTy::OPTIONAL);
+    return llvm::None;
+  }
+  ConstantInt *CI = dyn_cast_or_null<ConstantInt>(SimplifiedV.getValue());
+  if (CI)
+    A.recordDependence(ValueSimplifyAA, AA, DepClassTy::OPTIONAL);
+  return CI;
+}
+
 /// Recursively visit all values that might become \p IRP at some point. This
 /// will be done by looking through cast instructions, selects, phis, and calls
 /// with the "returned" attribute. Once we cannot look through the value any
@@ -2980,20 +3002,6 @@ identifyAliveSuccessors(Attributor &A, const InvokeInst &II,
   return UsedAssumedInformation;
 }
 
-static Optional<ConstantInt *>
-getAssumedConstant(Attributor &A, const Value &V, AbstractAttribute &AA,
-                   bool &UsedAssumedInformation) {
-  const auto &ValueSimplifyAA =
-      A.getAAFor<AAValueSimplify>(AA, IRPosition::value(V));
-  Optional<Value *> SimplifiedV = ValueSimplifyAA.getAssumedSimplifiedValue(A);
-  UsedAssumedInformation |= !ValueSimplifyAA.isKnown();
-  if (!SimplifiedV.hasValue())
-    return llvm::None;
-  if (isa_and_nonnull<UndefValue>(SimplifiedV.getValue()))
-    return llvm::None;
-  return dyn_cast_or_null<ConstantInt>(SimplifiedV.getValue());
-}
-
 static bool
 identifyAliveSuccessors(Attributor &A, const BranchInst &BI,
                         AbstractAttribute &AA,