[PATCH] D28009: [ConstantFolding] Fix vector GEPs harder

[Michael Kuperstein via Phabricator via llvm-commits]

mkuper created this revision.
mkuper added reviewers: davide, majnemer, loladiro.
mkuper added subscribers: llvm-commits, delena.

CastGEPIndices still handles Vector GEPs incorrectly - in some cases we can fall into an infinite recursion, because we compare the vector type to the scalar pointer type, and then try to cast a type to itself.


https://reviews.llvm.org/D28009

Files:
  lib/Analysis/ConstantFolding.cpp
  test/Analysis/ConstantFolding/vectorgep-crash.ll


Index: test/Analysis/ConstantFolding/vectorgep-crash.ll
===================================================================
--- test/Analysis/ConstantFolding/vectorgep-crash.ll
+++ test/Analysis/ConstantFolding/vectorgep-crash.ll
@@ -17,3 +17,24 @@
   %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 }
+
+ at 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
+}
Index: lib/Analysis/ConstantFolding.cpp
===================================================================
--- lib/Analysis/ConstantFolding.cpp
+++ lib/Analysis/ConstantFolding.cpp
@@ -742,13 +742,16 @@
     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]);
   }


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