Fixed a bug in narrowing store operation.

Type MVT::i1 became legal in KNL, but store operation can't be narrowed to this type,
since the size of VT (1 bit) is not equal to its actual store size(8 bits).

Added a test provided by David (dag@cray.com)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226805 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 849508891d3846a7f2e8df4eaff37a7b81934a4c..4a9ae200663e6a4d107535b7330ca68710e727b6 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -9497,9 +9497,12 @@ SDValue DAGCombiner::ReduceLoadOpStoreWidth(SDNode *N) {
     unsigned MSB = BitWidth - Imm.countLeadingZeros() - 1;
     unsigned NewBW = NextPowerOf2(MSB - ShAmt);
     EVT NewVT = EVT::getIntegerVT(*DAG.getContext(), NewBW);
+    // The narowwing should be profitable, the load/store operation should be
+    // legal (or custom) and the store size should be equal to the NewVT width.
     while (NewBW < BitWidth &&
-           !(TLI.isOperationLegalOrCustom(Opc, NewVT) &&
-             TLI.isNarrowingProfitable(VT, NewVT))) {
+           (NewVT.getStoreSizeInBits() != NewBW ||
+            !TLI.isOperationLegalOrCustom(Opc, NewVT) ||
+            !TLI.isNarrowingProfitable(VT, NewVT))) {
       NewBW = NextPowerOf2(NewBW);
       NewVT = EVT::getIntegerVT(*DAG.getContext(), NewBW);
     }

diff --git a/test/CodeGen/X86/i1narrowfail.ll b/test/CodeGen/X86/i1narrowfail.ll
new file mode 100644 (file)
index 0000000..e280f3c
--- /dev/null
+++ b/test/CodeGen/X86/i1narrowfail.ll
@@ -0,0 +1,10 @@
+; RUN: llc < %s -mtriple=x86_64-apple-darwin -mcpu=knl | FileCheck %s
+
+; CHECK-LABEL: @foo
+; CHECK: orb     $16
+define void @foo(i64* %ptr) {
+  %r11 = load i64* %ptr, align 8
+  %r12 = or i64 16, %r11
+  store i64 %r12, i64* %ptr, align 8
+  ret void
+}