From: Mon P Wang <wangmp@apple.com>
Date: Sat, 7 Feb 2009 22:19:29 +0000 (+0000)
Subject: Instrcombine should not change load(cast p) to cast(load p) if the cast
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=6753f959d2521cc67304d6d062008fa8f2fbfe23;p=oota-llvm.git

Instrcombine should not change load(cast p) to cast(load p) if the cast
changes the address space of the pointer.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64035 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 97af83f4e5d..b4262743a3c 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -11007,8 +11007,14 @@ static Instruction *InstCombineLoadCast(InstCombiner &IC, LoadInst &LI,
     }
   }
 
-  const Type *DestPTy = cast<PointerType>(CI->getType())->getElementType();
+  const PointerType *DestTy = cast<PointerType>(CI->getType());
+  const Type *DestPTy = DestTy->getElementType();
   if (const PointerType *SrcTy = dyn_cast<PointerType>(CastOp->getType())) {
+
+    // If the address spaces don't match, don't eliminate the cast.
+    if (DestTy->getAddressSpace() != SrcTy->getAddressSpace())
+      return 0;
+
     const Type *SrcPTy = SrcTy->getElementType();
 
     if (DestPTy->isInteger() || isa<PointerType>(DestPTy) || 
diff --git a/test/Transforms/InstCombine/cast_ld_addr_space.ll b/test/Transforms/InstCombine/cast_ld_addr_space.ll
new file mode 100644
index 00000000000..beb20e38545
--- /dev/null
+++ b/test/Transforms/InstCombine/cast_ld_addr_space.ll
@@ -0,0 +1,19 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep bitcast | count 1
+
+; InstCombine can not 'load (cast P)' -> cast (load P)' if the cast changes
+; the address space.
+
+
+define void @test2(i8 addrspace(1)* %source, <2 x i8> addrspace(1)* %dest) {                                                                                        
+entry: 
+  %arrayidx1 = bitcast <2 x i8> addrspace(1)* %dest to <2 x i8> addrspace(1)*
+  %conv = bitcast i8 addrspace(1)* %source to <16 x i8>*
+  %arrayidx22 = bitcast <16 x i8>* %conv to <16 x i8>*
+  %tmp3 = load <16 x i8>* %arrayidx22
+  %arrayidx223 = bitcast i8 addrspace(1)* %source to i8*
+  %tmp4 = load i8* %arrayidx223
+  %tmp5 = insertelement <2 x i8> undef, i8 %tmp4, i32 0
+  %splat = shufflevector <2 x i8> %tmp5, <2 x i8> undef, <2 x i32> zeroinitializer
+  store <2 x i8> %splat, <2 x i8> addrspace(1)* %arrayidx1
+  ret void                                                                                                                                                             
+} 
\ No newline at end of file