[PATCH] D119643: [Transforms] Enhance CorrelatedValuePropagation to handle both values of select

[Dmitry Vassiliev via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG90a3b3109170: [Transforms] Enhance CorrelatedValuePropagation to handle both values of select (authored by slydiman).

Changed prior to commit:
  https://reviews.llvm.org/D119643?vs=408410&id=410608#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D119643/new/

https://reviews.llvm.org/D119643

Files:
  llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
  llvm/test/Transforms/CorrelatedValuePropagation/basic.ll


Index: llvm/test/Transforms/CorrelatedValuePropagation/basic.ll
===================================================================
--- llvm/test/Transforms/CorrelatedValuePropagation/basic.ll
+++ llvm/test/Transforms/CorrelatedValuePropagation/basic.ll
@@ -179,9 +179,8 @@
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br label [[LOOP:%.*]]
 ; CHECK:       loop:
-;; CorrelatedValuePropagation should handle inverted select condition, but it does not yet.
-;; CHECK-NEXT:    [[PHI:%.*]] = phi i32* [ [[F:%.*]], [[LOOP]] ], [ [[X:%.*]], [[ENTRY:%.*]] ]
-; CHECK-NEXT:    [[F:%.*]] = tail call i32* @f(i32* [[PHI]])
+; CHECK-NEXT:    [[PHI:%.*]] = phi i32* [ [[F:%.*]], [[LOOP]] ], [ [[X:%.*]], [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[F]] = tail call i32* @f(i32* [[PHI]])
 ; CHECK-NEXT:    [[CMP1:%.*]] = icmp eq i32* [[F]], [[Y:%.*]]
 ; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32* null, i32* [[F]]
 ; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i32* [[SEL]], null
Index: llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
+++ llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
@@ -245,11 +245,20 @@
   // value can never be that constant. In that case replace the incoming
   // value with the other value of the select. This often allows us to
   // remove the select later.
+
+  // The "false" case
   if (auto *C = dyn_cast<Constant>(SI->getFalseValue()))
     if (LVI->getPredicateOnEdge(ICmpInst::ICMP_EQ, SI, C, From, To, CxtI) ==
         LazyValueInfo::False)
       return SI->getTrueValue();
 
+  // The "true" case,
+  // similar to the select "false" case, but try the select "true" value
+  if (auto *C = dyn_cast<Constant>(SI->getTrueValue()))
+    if (LVI->getPredicateOnEdge(ICmpInst::ICMP_EQ, SI, C, From, To, CxtI) ==
+        LazyValueInfo::False)
+      return SI->getFalseValue();
+
   return nullptr;
 }
 


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