[PATCH] D98672: [InstSimplify] Match PtrToInt more directly in a GEP transform (NFC)

[Simonas Kazlauskas via Phabricator via llvm-commits]

nagisa created this revision.
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In preparation for D98611 <https://reviews.llvm.org/D98611>, the upcoming change will need to apply additional checks to `P` and `V`,
and so this refactor paves the way for adding additional checks in a less awkward way.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D98672

Files:
  llvm/lib/Analysis/InstructionSimplify.cpp


Index: llvm/lib/Analysis/InstructionSimplify.cpp
===================================================================
--- llvm/lib/Analysis/InstructionSimplify.cpp
+++ llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4349,40 +4349,31 @@
       // doesn't truncate the pointers.
       if (Ops[1]->getType()->getScalarSizeInBits() ==
           Q.DL.getPointerSizeInBits(AS)) {
-        auto PtrToInt = [GEPTy](Value *P) -> Value * {
-          Value *Temp;
-          if (match(P, m_PtrToInt(m_Value(Temp))))
-            if (Temp->getType() == GEPTy)
-              return Temp;
-          return nullptr;
+        auto CanSimplify = [GEPTy, &P]() -> bool {
+          return P->getType() == GEPTy;
         };
-
-        // FIXME: The following transforms are only legal if P and V have the
-        // same provenance (PR44403). Check whether getUnderlyingObject() is
-        // the same?
-
         // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
         if (TyAllocSize == 1 &&
-            match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0])))))
-          if (Value *R = PtrToInt(P))
-            return R;
-
-        // getelementptr V, (ashr (sub P, V), C) -> Q
-        // if P points to a type of size 1 << C.
-        if (match(Ops[1],
-                  m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
-                         m_ConstantInt(C))) &&
-            TyAllocSize == 1ULL << C)
-          if (Value *R = PtrToInt(P))
-            return R;
-
-        // getelementptr V, (sdiv (sub P, V), C) -> Q
-        // if P points to a type of size C.
-        if (match(Ops[1],
-                  m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))),
-                         m_SpecificInt(TyAllocSize))))
-          if (Value *R = PtrToInt(P))
-            return R;
+            match(Ops[1], m_Sub(m_PtrToInt(m_Value(P)),
+                                m_PtrToInt(m_Specific(Ops[0])))) &&
+            CanSimplify())
+          return P;
+
+        // getelementptr V, (ashr (sub P, V), C) -> P if P points to a type of
+        // size 1 << C.
+        if (match(Ops[1], m_AShr(m_Sub(m_PtrToInt(m_Value(P)),
+                                       m_PtrToInt(m_Specific(Ops[0]))),
+                                 m_ConstantInt(C))) &&
+            TyAllocSize == 1ULL << C && CanSimplify())
+          return P;
+
+        // getelementptr V, (sdiv (sub P, V), C) -> P if P points to a type of
+        // size C.
+        if (match(Ops[1], m_SDiv(m_Sub(m_PtrToInt(m_Value(P)),
+                                       m_PtrToInt(m_Specific(Ops[0]))),
+                                 m_SpecificInt(TyAllocSize))) &&
+            CanSimplify())
+          return P;
       }
     }
   }


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