From 6fa08aafcce77c519b19c605c6cb2853ca2a35ea Mon Sep 17 00:00:00 2001
From: Sanjoy Das <sanjoy@playingwithpointers.com>
Date: Fri, 5 Aug 2016 19:23:29 +0000
Subject: [PATCH] [ConstantFolding] Don't create illegal (non-integral)
 inttoptrs

Reviewers: majnemer, arsenm

Subscribers: mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D23182

llvm-svn: 277854
---
 llvm/lib/Analysis/ConstantFolding.cpp                |  7 ++++---
 .../Transforms/InstCombine/non-integral-pointers.ll  | 20 ++++++++++++++++++++
 2 files changed, 24 insertions(+), 3 deletions(-)
 create mode 100644 llvm/test/Transforms/InstCombine/non-integral-pointers.ll

diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index 39e422f..a7fb10b 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -828,7 +828,9 @@ Constant *SymbolicallyEvaluateGEP(const GEPOperator *GEP,
     }
   }
 
-  if (Ptr->isNullValue() || BasePtr != 0) {
+  auto *PTy = cast<PointerType>(Ptr->getType());
+  if ((Ptr->isNullValue() || BasePtr != 0) &&
+      !DL.isNonIntegralPointerType(PTy)) {
     Constant *C = ConstantInt::get(Ptr->getContext(), Offset + BasePtr);
     return ConstantExpr::getIntToPtr(C, ResTy);
   }
@@ -837,8 +839,7 @@ Constant *SymbolicallyEvaluateGEP(const GEPOperator *GEP,
   // we eliminate over-indexing of the notional static type array bounds.
   // This makes it easy to determine if the getelementptr is "inbounds".
   // Also, this helps GlobalOpt do SROA on GlobalVariables.
-  Type *Ty = Ptr->getType();
-  assert(Ty->isPointerTy() && "Forming regular GEP of non-pointer type");
+  Type *Ty = PTy;
   SmallVector<Constant *, 32> NewIdxs;
 
   do {
diff --git a/llvm/test/Transforms/InstCombine/non-integral-pointers.ll b/llvm/test/Transforms/InstCombine/non-integral-pointers.ll
new file mode 100644
index 0000000..d5e2569
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/non-integral-pointers.ll
@@ -0,0 +1,20 @@
+; RUN: opt -instcombine -S < %s | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128-ni:4"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i8 addrspace(4)* @f_0() {
+; CHECK-LABEL: @f_0(
+; CHECK: ret i8 addrspace(4)* getelementptr (i8, i8 addrspace(4)* null, i64 50)
+  %result = getelementptr i8, i8 addrspace(4)* null, i64 50
+  ret i8 addrspace(4)* %result
+}
+
+define i8 addrspace(3)* @f_1() {
+; inttoptr is fine here since addrspace(3) is integral.
+
+; CHECK-LABEL: @f_1(
+; CHECK: ret i8 addrspace(3)* inttoptr (i64 50 to i8 addrspace(3)*)
+  %result = getelementptr i8, i8 addrspace(3)* null, i64 50
+  ret i8 addrspace(3)* %result
+}
-- 
2.7.4