[InstCombine] Perform common cast transforms for ptrtoaddr

Author: nikic

llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp

@@ -2202,6 +2202,11 @@ Instruction *InstCombinerImpl::visitPtrToInt(PtrToIntInst &CI) {
   return commonCastTransforms(CI);
 }
 
+Instruction *InstCombinerImpl::visitPtrToAddr(PtrToAddrInst &CI) {
+  // FIXME: Implement variants of ptrtoint folds.
+  return commonCastTransforms(CI);
+}
+
 /// This input value (which is known to have vector type) is being zero extended
 /// or truncated to the specified vector type. Since the zext/trunc is done
 /// using an integer type, we have a (bitcast(cast(bitcast))) pattern,

llvm/lib/Transforms/InstCombine/InstCombineInternal.h

@@ -143,6 +143,7 @@ class LLVM_LIBRARY_VISIBILITY InstCombinerImpl final
   Instruction *visitUIToFP(CastInst &CI);
   Instruction *visitSIToFP(CastInst &CI);
   Instruction *visitPtrToInt(PtrToIntInst &CI);
+  Instruction *visitPtrToAddr(PtrToAddrInst &CI);
   Instruction *visitIntToPtr(IntToPtrInst &CI);
   Instruction *visitBitCast(BitCastInst &CI);
   Instruction *visitAddrSpaceCast(AddrSpaceCastInst &CI);

llvm/test/Transforms/InstCombine/ptrtoaddr.ll

@@ -10,8 +10,18 @@ target datalayout = "pe1:64:64:64:32"
 @g.as1 = external addrspace(1) global i8
 @g2.as1 = external addrspace(1) global i8
 
-define i32 @ptrtoaddr_inttoptr_arg(i32 %a) {
-; CHECK-LABEL: define i32 @ptrtoaddr_inttoptr_arg(
+define i64 @ptrtoaddr_inttoptr_arg(i64 %a) {
+; CHECK-LABEL: define i64 @ptrtoaddr_inttoptr_arg(
+; CHECK-SAME: i64 [[A:%.*]]) {
+; CHECK-NEXT:    ret i64 [[A]]
+;
+  %toptr = inttoptr i64 %a to ptr
+  %toaddr = ptrtoaddr ptr %toptr to i64
+  ret i64 %toaddr
+}
+
+define i32 @ptrtoaddr_inttoptr_arg_addrsize(i32 %a) {
+; CHECK-LABEL: define i32 @ptrtoaddr_inttoptr_arg_addrsize(
 ; CHECK-SAME: i32 [[A:%.*]]) {
 ; CHECK-NEXT:    [[TMP1:%.*]] = zext i32 [[A]] to i64
 ; CHECK-NEXT:    [[TOPTR:%.*]] = inttoptr i64 [[TMP1]] to ptr addrspace(1)