[llvm] r302447 - ConstantFold: Handle gep nonnull, undef as well

[Daniel Berlin via llvm-commits]

Author: dannyb
Date: Mon May  8 12:37:33 2017
New Revision: 302447

URL: http://llvm.org/viewvc/llvm-project?rev=302447&view=rev
Log:
ConstantFold: Handle gep nonnull, undef as well

Modified:
    llvm/trunk/lib/IR/ConstantFold.cpp
    llvm/trunk/test/Transforms/Inline/inline-constexpr-addrspacecast-argument.ll

Modified: llvm/trunk/lib/IR/ConstantFold.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/ConstantFold.cpp?rev=302447&r1=302446&r2=302447&view=diff
==============================================================================
--- llvm/trunk/lib/IR/ConstantFold.cpp (original)
+++ llvm/trunk/lib/IR/ConstantFold.cpp Mon May  8 12:37:33 2017
@@ -2041,9 +2041,6 @@ Constant *llvm::ConstantFoldGetElementPt
                                           Optional<unsigned> InRangeIndex,
                                           ArrayRef<Value *> Idxs) {
   if (Idxs.empty()) return C;
-  Constant *Idx0 = cast<Constant>(Idxs[0]);
-  if ((Idxs.size() == 1 && Idx0->isNullValue()))
-    return C;
 
   if (isa<UndefValue>(C)) {
     Type *GEPTy = GetElementPtrInst::getGEPReturnType(
@@ -2051,6 +2048,10 @@ Constant *llvm::ConstantFoldGetElementPt
     return UndefValue::get(GEPTy);
   }
 
+  Constant *Idx0 = cast<Constant>(Idxs[0]);
+  if (Idxs.size() == 1 && (Idx0->isNullValue() || isa<UndefValue>(Idx0)))
+    return C;
+
   if (C->isNullValue()) {
     bool isNull = true;
     for (unsigned i = 0, e = Idxs.size(); i != e; ++i)

Modified: llvm/trunk/test/Transforms/Inline/inline-constexpr-addrspacecast-argument.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Inline/inline-constexpr-addrspacecast-argument.ll?rev=302447&r1=302446&r2=302447&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/Inline/inline-constexpr-addrspacecast-argument.ll (original)
+++ llvm/trunk/test/Transforms/Inline/inline-constexpr-addrspacecast-argument.ll Mon May  8 12:37:33 2017
@@ -6,7 +6,7 @@ target datalayout = "e-p3:32:32-p4:64:64
 @lds = internal addrspace(3) global [64 x i64] zeroinitializer
 
 ; CHECK-LABEL: @constexpr_addrspacecast_ptr_size_change(
-; CHECK: load i64, i64 addrspace(4)* getelementptr (i64, i64 addrspace(4)* addrspacecast (i64 addrspace(3)* getelementptr inbounds ([64 x i64], [64 x i64] addrspace(3)* @lds, i32 0, i32 0) to i64 addrspace(4)*), i64 undef)
+; CHECK: load i64, i64 addrspace(4)* addrspacecast (i64 addrspace(3)* getelementptr inbounds ([64 x i64], [64 x i64] addrspace(3)* @lds, i32 0, i32 0) to i64 addrspace(4)*)
 ; CHECK-NEXT: br
 define void @constexpr_addrspacecast_ptr_size_change() #0 {
   %tmp0 = call i32 @foo(i64 addrspace(4)* addrspacecast (i64 addrspace(3)* getelementptr inbounds ([64 x i64], [64 x i64] addrspace(3)* @lds, i32 0, i32 0) to i64 addrspace(4)*)) #1