[llvm] a977324 - [InstSimplify] Match PtrToInt more directly in a GEP transform (NFC)

[Simonas Kazlauskas via llvm-commits]

Author: Simonas Kazlauskas
Date: 2021-03-16T15:45:19+02:00
New Revision: a9773248001229ed67f239c7ebb2043f7e9ddb94

URL: https://github.com/llvm/llvm-project/commit/a9773248001229ed67f239c7ebb2043f7e9ddb94
DIFF: https://github.com/llvm/llvm-project/commit/a9773248001229ed67f239c7ebb2043f7e9ddb94.diff

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

In preparation for 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.

Reviewed By: lebedev.ri

Differential Revision: https://reviews.llvm.org/D98672

Added: 
    

Modified: 
    llvm/lib/Analysis/InstructionSimplify.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 5e05cb03d831..95a4e8d82c76 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4349,40 +4349,34 @@ static Value *SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops,
       // 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 {
+          // FIXME: The following transforms are only legal if P and V have the
+          // same provenance (PR44403). Check whether getUnderlyingObject() is
+          // the same?
+          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;
       }
     }
   }