[ConstantFolding] Fix vector GEPs harder

For vector GEPs, CastGEPIndices can end up in an infinite recursion, because
we compare the vector type to the scalar pointer type, find them different,
and then try to cast a type to itself.

Differential Revision: https://reviews.llvm.org/D28009

llvm-svn: 290260

2 files changed, 27 insertions, 3 deletions

diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index cf0d5e4ec79..9e521e12d5a 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -742,13 +742,16 @@ Constant *CastGEPIndices(Type *SrcElemTy, ArrayRef<Constant *> Ops,
     if ((i == 1 ||
          !isa<StructType>(GetElementPtrInst::getIndexedType(
              SrcElemTy, Ops.slice(1, i - 1)))) &&
-        Ops[i]->getType() != (i == 1 ? IntPtrTy : IntPtrScalarTy)) {
+        Ops[i]->getType()->getScalarType() != IntPtrScalarTy) {
       Any = true;
+      Type *NewType = Ops[i]->getType()->isVectorTy()
+                          ? IntPtrTy
+                          : IntPtrTy->getScalarType();
       NewIdxs.push_back(ConstantExpr::getCast(CastInst::getCastOpcode(Ops[i],
                                                                       true,
-                                                                      IntPtrTy,
+                                                                      NewType,
                                                                       true),
-                                              Ops[i], IntPtrTy));
+                                              Ops[i], NewType));
     } else
       NewIdxs.push_back(Ops[i]);
   }
diff --git a/llvm/test/Analysis/ConstantFolding/vectorgep-crash.ll b/llvm/test/Analysis/ConstantFolding/vectorgep-crash.ll
index bcc96b2676b..e7a5117d6ed 100644
--- a/llvm/test/Analysis/ConstantFolding/vectorgep-crash.ll
+++ b/llvm/test/Analysis/ConstantFolding/vectorgep-crash.ll
@@ -17,3 +17,24 @@ top:
   %0 = bitcast <8 x double*> %VectorGep14 to <8 x i64*>
   ret <8 x i64*> %0
 }
+
+%struct.A = type { i32, %struct.B* }
+%struct.B = type { i64, %struct.C* }
+%struct.C = type { i64 }
+
+@G = internal global [65 x %struct.A] zeroinitializer, align 16
+; CHECK-LABEL: @test
+; CHECK: ret <16 x i32*> getelementptr ([65 x %struct.A], [65 x %struct.A]* @G, <16 x i64> zeroinitializer, <16 x i64> <i64 1, i64 2, i64 3, i64 4, i64 5, i64 6, i64 7, i64 8, i64 9, i64 10, i64 11, i64 12, i64 13, i64 14, i64 15, i64 16>, <16 x i32> zeroinitializer)
+define <16 x i32*> @test() {
+vector.body:
+  %VectorGep = getelementptr [65 x %struct.A], [65 x %struct.A]* @G, <16 x i64> zeroinitializer, <16 x i64> <i64 1, i64 2, i64 3, i64 4, i64 5, i64 6, i64 7, i64 8, i64 9, i64 10, i64 11, i64 12, i64 13, i64 14, i64 15, i64 16>, <16 x i32> zeroinitializer
+  ret <16 x i32*> %VectorGep
+}
+
+; CHECK-LABEL: @test2
+; CHECK: ret <16 x i32*> getelementptr ([65 x %struct.A], [65 x %struct.A]* @G, <16 x i64> zeroinitializer, <16 x i64> <i64 1, i64 2, i64 3, i64 4, i64 5, i64 6, i64 7, i64 8, i64 9, 
+define <16 x i32*> @test2() {
+vector.body:
+  %VectorGep = getelementptr [65 x %struct.A], [65 x %struct.A]* @G, <16 x i32> zeroinitializer, <16 x i64> <i64 1, i64 2, i64 3, i64 4, i64 5, i64 6, i64 7, i64 8, i64 9, i64 10, i64 11, i64 12, i64 13, i64 14, i64 15, i64 16>, <16 x i32> zeroinitializer
+  ret <16 x i32*> %VectorGep
+}