[GVN] Add support for ptrtoaddr

Author: nikic

llvm/lib/Transforms/Scalar/GVN.cpp

@@ -699,6 +699,7 @@ uint32_t GVNPass::ValueTable::lookupOrAdd(Value *V) {
     case Instruction::FPTrunc:
     case Instruction::FPExt:
     case Instruction::PtrToInt:
+    case Instruction::PtrToAddr:
     case Instruction::IntToPtr:
     case Instruction::AddrSpaceCast:
     case Instruction::BitCast:

llvm/test/Transforms/GVN/ptrtoaddr.ll

@@ -4,10 +4,8 @@
 define i64 @ptrtoaddr_same(ptr %p) {
 ; CHECK-LABEL: define i64 @ptrtoaddr_same(
 ; CHECK-SAME: ptr [[P:%.*]]) {
-; CHECK-NEXT:    [[I:%.*]] = ptrtoaddr ptr [[P]] to i64
 ; CHECK-NEXT:    [[J:%.*]] = ptrtoaddr ptr [[P]] to i64
-; CHECK-NEXT:    [[SUB:%.*]] = sub i64 [[I]], [[J]]
-; CHECK-NEXT:    ret i64 [[SUB]]
+; CHECK-NEXT:    ret i64 0
 ;
   %i = ptrtoaddr ptr %p to i64
   %j = ptrtoaddr ptr %p to i64