Fix shl folding in DAG combiner.

Summary: The code responsible for shl folding in the DAGCombiner was assuming incorrectly that all constants are less than 64 bits. This patch simply changes the way values are compared.

Test Plan: A regression test included.

Reviewers: andreadb

Reviewed By: andreadb

Subscribers: andreadb, test, llvm-commits

Differential Revision: http://reviews.llvm.org/D10602

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240291 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index bc2e5f13d4384faf2dc84210a27adb3321460518..80a1b5b3be79bb386efd966342de49fea3bdd9e1 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4275,7 +4275,7 @@ SDValue DAGCombiner::visitSHL(SDNode *N) {
   if (isNullConstant(N0))
     return N0;
   // fold (shl x, c >= size(x)) -> undef
-  if (N1C && N1C->getZExtValue() >= OpSizeInBits)
+  if (N1C && N1C->getAPIntValue().uge(OpSizeInBits))
     return DAG.getUNDEF(VT);
   // fold (shl x, 0) -> x
   if (N1C && N1C->isNullValue())

diff --git a/test/CodeGen/X86/fold-vector-shl-crash.ll b/test/CodeGen/X86/fold-vector-shl-crash.ll
new file mode 100644 (file)
index 0000000..b0341e0
--- /dev/null
+++ b/test/CodeGen/X86/fold-vector-shl-crash.ll
@@ -0,0 +1,8 @@
+; RUN: llc < %s | FileCheck %s
+
+;CHECK-LABEL: test
+define <2 x i256> @test() {
+  %S = shufflevector <2 x i256> zeroinitializer, <2 x i256> <i256 -1, i256 -1>, <2 x i32> <i32 0, i32 2>
+  %B = shl <2 x i256> %S, <i256 -1, i256 -1> ; DAG Combiner crashes here
+  ret <2 x i256> %B
+}