From a069c6ce05736625a9b066572b3ecc7996e01a8f Mon Sep 17 00:00:00 2001
From: Nadav Rotem <nadav.rotem@intel.com>
Date: Tue, 5 Apr 2011 14:29:52 +0000
Subject: InstCombine optimizes gep(bitcast(x)) even when the bitcasts casts
 away address space info. We crash with an assert in this case. This change
 checks that the address space of the bitcasted pointer is the same as the gep
 ptr.

llvm-svn: 128884
---
 .../Transforms/InstCombine/InstructionCombining.cpp   | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

(limited to 'llvm/lib/Transforms')

diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 21851768cbb..4be671f031e 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -849,22 +849,23 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
         GetElementPtrInst::Create(Src->getOperand(0), Indices.begin(),
                                   Indices.end(), GEP.getName());
   }
-  
+
   // Handle gep(bitcast x) and gep(gep x, 0, 0, 0).
   Value *StrippedPtr = PtrOp->stripPointerCasts();
-  if (StrippedPtr != PtrOp) {
-    const PointerType *StrippedPtrTy =cast<PointerType>(StrippedPtr->getType());
+  const PointerType *StrippedPtrTy =cast<PointerType>(StrippedPtr->getType());
+  if (StrippedPtr != PtrOp &&
+    StrippedPtrTy->getAddressSpace() == GEP.getPointerAddressSpace()) {
 
     bool HasZeroPointerIndex = false;
     if (ConstantInt *C = dyn_cast<ConstantInt>(GEP.getOperand(1)))
       HasZeroPointerIndex = C->isZero();
-    
+
     // Transform: GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ...
     // into     : GEP [10 x i8]* X, i32 0, ...
     //
     // Likewise, transform: GEP (bitcast i8* X to [0 x i8]*), i32 0, ...
     //           into     : GEP i8* X, ...
-    // 
+    //
     // This occurs when the program declares an array extern like "int X[];"
     if (HasZeroPointerIndex) {
       const PointerType *CPTy = cast<PointerType>(PtrOp->getType());
@@ -975,7 +976,7 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
       }
     }
   }
-  
+
   /// See if we can simplify:
   ///   X = bitcast A* to B*
   ///   Y = gep X, <...constant indices...>
@@ -983,12 +984,14 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
   /// analysis of unions.  If "A" is also a bitcast, wait for A/X to be merged.
   if (BitCastInst *BCI = dyn_cast<BitCastInst>(PtrOp)) {
     if (TD &&
-        !isa<BitCastInst>(BCI->getOperand(0)) && GEP.hasAllConstantIndices()) {
+        !isa<BitCastInst>(BCI->getOperand(0)) && GEP.hasAllConstantIndices() &&
+        StrippedPtrTy->getAddressSpace() == GEP.getPointerAddressSpace()) {
+
       // Determine how much the GEP moves the pointer.  We are guaranteed to get
       // a constant back from EmitGEPOffset.
       ConstantInt *OffsetV = cast<ConstantInt>(EmitGEPOffset(&GEP));
       int64_t Offset = OffsetV->getSExtValue();
-      
+
       // If this GEP instruction doesn't move the pointer, just replace the GEP
       // with a bitcast of the real input to the dest type.
       if (Offset == 0) {
-- 
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