Fix bug where ReduceLoadWidth was creating illegal ZEXTLOAD instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124587 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 94487d40414562d8ab4da20bda37968ff62da978..e91592b2429be2523e1473dafb629e1f3937f474 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4244,8 +4244,6 @@ SDValue DAGCombiner::ReduceLoadWidth(SDNode *N) {
   if (Opc == ISD::SIGN_EXTEND_INREG) {
     ExtType = ISD::SEXTLOAD;
     ExtVT = cast<VTSDNode>(N->getOperand(1))->getVT();
-    if (LegalOperations && !TLI.isLoadExtLegal(ISD::SEXTLOAD, ExtVT))
-      return SDValue();
   } else if (Opc == ISD::SRL) {
     // Another special-case: SRL is basically zero-extending a narrower value.
     ExtType = ISD::ZEXTLOAD;
@@ -4255,6 +4253,8 @@ SDValue DAGCombiner::ReduceLoadWidth(SDNode *N) {
     ExtVT = EVT::getIntegerVT(*DAG.getContext(),
                               VT.getSizeInBits() - N01->getZExtValue());
   }
+  if (LegalOperations && !TLI.isLoadExtLegal(ExtType, ExtVT))
+    return SDValue();
 
   unsigned EVTBits = ExtVT.getSizeInBits();
   

diff --git a/test/CodeGen/XCore/2011-01-31-DAGCombineBug.ll b/test/CodeGen/XCore/2011-01-31-DAGCombineBug.ll
new file mode 100644 (file)
index 0000000..f8fe0d2
--- /dev/null
+++ b/test/CodeGen/XCore/2011-01-31-DAGCombineBug.ll
@@ -0,0 +1,10 @@
+; RUN: llc < %s -march=xcore
+%struct.st = type <{ i8, i32, i8, i32, i8, i32 }>
+
+@x = external global %struct.st, align 4
+
+define i32 @test_entry() nounwind {
+entry:
+  %0 = load i32* getelementptr inbounds (%struct.st* @x, i32 0, i32 3), align 2
+  ret i32 %0
+}