Reapply r240291: Fix shl folding in DAG combiner.

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.

It has been reverted previously because of some problems with comparing APInt with raw uint64_t. That has been fixed/changed with r241204.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241254 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 631f5852334e56068b2f575deb842fed95e4b8e8..6056d93ddc7a6a0d7b4364232fee2ddf677786ea 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4278,7 +4278,7 @@ 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..9f81e44
--- /dev/null
+++ b/test/CodeGen/X86/fold-vector-shl-crash.ll
@@ -0,0 +1,9 @@
+; RUN: llc < %s -march=x86-64 | FileCheck %s
+; RUN: llc < %s -march=x86    | 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
+}