[InstCombine] Factor the logic for propagating !nonnull and !range

metadata out of InstCombine and into helpers.

NFC, this just exposes the logic used by InstCombine when propagating
metadata from one load instruction to another. The plan is to use this
in SROA to address PR32902.

If anyone has better ideas about how to factor this or name variables,
I'm all ears, but this seemed like a pretty good start and lets us make
progress on the PR.

This is based on a patch by Ariel Ben-Yehuda (D34285).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306267 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Transforms/Utils/Local.h b/include/llvm/Transforms/Utils/Local.h
index 8fed292e77a37a28414df4d02ff871a59bde7636..30b27616cd9827bbdbde16009172a87b18738485 100644 (file)
--- a/include/llvm/Transforms/Utils/Local.h
+++ b/include/llvm/Transforms/Utils/Local.h
@@ -380,6 +380,19 @@ unsigned replaceDominatedUsesWith(Value *From, Value *To, DominatorTree &DT,
 /// during lowering by the GC infrastructure.
 bool callsGCLeafFunction(ImmutableCallSite CS);
 
+/// Copy a nonnull metadata node to a new load instruction.
+///
+/// This handles mapping it to range metadata if the new load is an integer
+/// load instead of a pointer load.
+void copyNonnullMetadata(const LoadInst &OldLI, MDNode *N, LoadInst &NewLI);
+
+/// Copy a range metadata node to a new load instruction.
+///
+/// This handles mapping it to nonnull metadata if the new load is a pointer
+/// load instead of an integer load and the range doesn't cover null.
+void copyRangeMetadata(const DataLayout &DL, const LoadInst &OldLI, MDNode *N,
+                       LoadInst &NewLI);
+
 //===----------------------------------------------------------------------===//
 //  Intrinsic pattern matching
 //

diff --git a/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
index ee30aa44674304401988dacf58eadce241ee757e..ca370c73fca44c195a0be4b6f1f5c705a8c1ee57 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ b/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -489,21 +489,7 @@ static LoadInst *combineLoadToNewType(InstCombiner &IC, LoadInst &LI, Type *NewT
       break;
 
     case LLVMContext::MD_nonnull:
-      // This only directly applies if the new type is also a pointer.
-      if (NewTy->isPointerTy()) {
-        NewLoad->setMetadata(ID, N);
-        break;
-      }
-      // If it's integral now, translate it to !range metadata.
-      if (NewTy->isIntegerTy()) {
-        auto *ITy = cast<IntegerType>(NewTy);
-        auto *NullInt = ConstantExpr::getPtrToInt(
-            ConstantPointerNull::get(cast<PointerType>(Ptr->getType())), ITy);
-        auto *NonNullInt =
-            ConstantExpr::getAdd(NullInt, ConstantInt::get(ITy, 1));
-        NewLoad->setMetadata(LLVMContext::MD_range,
-                             MDB.createRange(NonNullInt, NullInt));
-      }
+      copyNonnullMetadata(LI, N, *NewLoad);
       break;
     case LLVMContext::MD_align:
     case LLVMContext::MD_dereferenceable:
@@ -513,17 +499,7 @@ static LoadInst *combineLoadToNewType(InstCombiner &IC, LoadInst &LI, Type *NewT
         NewLoad->setMetadata(ID, N);
       break;
     case LLVMContext::MD_range:
-      // FIXME: It would be nice to propagate this in some way, but the type
-      // conversions make it hard.
-
-      // If it's a pointer now and the range does not contain 0, make it !nonnull.
-      if (NewTy->isPointerTy()) {
-        unsigned BitWidth = IC.getDataLayout().getTypeSizeInBits(NewTy);
-        if (!getConstantRangeFromMetadata(*N).contains(APInt(BitWidth, 0))) {
-          MDNode *NN = MDNode::get(LI.getContext(), None);
-          NewLoad->setMetadata(LLVMContext::MD_nonnull, NN);
-        }
-      }
+      copyRangeMetadata(IC.getDataLayout(), LI, N, *NewLoad);
       break;
     }
   }

diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp
index 2af671636cbdb11be6ce71162a715e6fa7bd48af..5127eba3f9aeaabab4300878399fa8d4071f0bda 100644 (file)
--- a/lib/Transforms/Utils/Local.cpp
+++ b/lib/Transforms/Utils/Local.cpp
@@ -26,6 +26,7 @@
 #include "llvm/Analysis/MemoryBuiltins.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/CFG.h"
+#include "llvm/IR/ConstantRange.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DIBuilder.h"
 #include "llvm/IR/DataLayout.h"
@@ -1081,7 +1082,7 @@ static bool LdStHasDebugValue(DILocalVariable *DIVar, DIExpression *DIExpr,
 }
 
 /// See if there is a dbg.value intrinsic for DIVar for the PHI node.
-static bool PhiHasDebugValue(DILocalVariable *DIVar, 
+static bool PhiHasDebugValue(DILocalVariable *DIVar,
                              DIExpression *DIExpr,
                              PHINode *APN) {
   // Since we can't guarantee that the original dbg.declare instrinsic
@@ -1159,7 +1160,7 @@ void llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
   DbgValue->insertAfter(LI);
 }
 
-/// Inserts a llvm.dbg.value intrinsic after a phi 
+/// Inserts a llvm.dbg.value intrinsic after a phi
 /// that has an associated llvm.dbg.decl intrinsic.
 void llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
                                            PHINode *APN, DIBuilder &Builder) {
@@ -1742,12 +1743,12 @@ void llvm::combineMetadata(Instruction *K, const Instruction *J,
         // Preserve !invariant.group in K.
         break;
       case LLVMContext::MD_align:
-        K->setMetadata(Kind, 
+        K->setMetadata(Kind,
           MDNode::getMostGenericAlignmentOrDereferenceable(JMD, KMD));
         break;
       case LLVMContext::MD_dereferenceable:
       case LLVMContext::MD_dereferenceable_or_null:
-        K->setMetadata(Kind, 
+        K->setMetadata(Kind,
           MDNode::getMostGenericAlignmentOrDereferenceable(JMD, KMD));
         break;
     }
@@ -1847,6 +1848,49 @@ bool llvm::callsGCLeafFunction(ImmutableCallSite CS) {
   return false;
 }
 
+void llvm::copyNonnullMetadata(const LoadInst &OldLI, MDNode *N,
+                               LoadInst &NewLI) {
+  auto *NewTy = NewLI.getType();
+
+  // This only directly applies if the new type is also a pointer.
+  if (NewTy->isPointerTy()) {
+    NewLI.setMetadata(LLVMContext::MD_nonnull, N);
+    return;
+  }
+
+  // The only other translation we can do is to integral loads with !range
+  // metadata.
+  if (!NewTy->isIntegerTy())
+    return;
+
+  MDBuilder MDB(NewLI.getContext());
+  const Value *Ptr = OldLI.getPointerOperand();
+  auto *ITy = cast<IntegerType>(NewTy);
+  auto *NullInt = ConstantExpr::getPtrToInt(
+      ConstantPointerNull::get(cast<PointerType>(Ptr->getType())), ITy);
+  auto *NonNullInt = ConstantExpr::getAdd(NullInt, ConstantInt::get(ITy, 1));
+  NewLI.setMetadata(LLVMContext::MD_range,
+                    MDB.createRange(NonNullInt, NullInt));
+}
+
+void llvm::copyRangeMetadata(const DataLayout &DL, const LoadInst &OldLI,
+                             MDNode *N, LoadInst &NewLI) {
+  auto *NewTy = NewLI.getType();
+
+  // Give up unless it is converted to a pointer where there is a single very
+  // valuable mapping we can do reliably.
+  // FIXME: It would be nice to propagate this in more ways, but the type
+  // conversions make it hard.
+  if (!NewTy->isPointerTy())
+    return;
+
+  unsigned BitWidth = DL.getTypeSizeInBits(NewTy);
+  if (!getConstantRangeFromMetadata(*N).contains(APInt(BitWidth, 0))) {
+    MDNode *NN = MDNode::get(OldLI.getContext(), None);
+    NewLI.setMetadata(LLVMContext::MD_nonnull, NN);
+  }
+}
+
 namespace {
 /// A potential constituent of a bitreverse or bswap expression. See
 /// collectBitParts for a fuller explanation.
@@ -1968,7 +2012,7 @@ collectBitParts(Value *V, bool MatchBSwaps, bool MatchBitReversals,
       unsigned NumMaskedBits = AndMask.countPopulation();
       if (!MatchBitReversals && NumMaskedBits % 8 != 0)
         return Result;
-      
+
       auto &Res = collectBitParts(I->getOperand(0), MatchBSwaps,
                                   MatchBitReversals, BPS);
       if (!Res)