Fix a bug in DAGcombiner about zero-extend after setcc.

For AArch64 backend, if DAGCombiner see "sext(setcc)", it will
combine them together to a single setcc with extended value type.
Then if it see "zext(setcc)", it assumes setcc is Vxi1, and try to
create "(and (vsetcc), (1, 1, ...)". While setcc isn't Vxi1,
DAGcombiner will create wrong node and get wrong code emitted.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198190 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 68d0521e7630a9a76686ea740d33b617d2793994..3b87922b7897fad8d2c5c3b3d5cfe80e4dadbb01 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4970,7 +4970,8 @@ SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) {
   }
 
   if (N0.getOpcode() == ISD::SETCC) {
-    if (!LegalOperations && VT.isVector()) {
+    if (!LegalOperations && VT.isVector() &&
+        N0.getValueType().getVectorElementType() == MVT::i1) {
       // zext(setcc) -> (and (vsetcc), (1, 1, ...) for vectors.
       // Only do this before legalize for now.
       EVT N0VT = N0.getOperand(0).getValueType();

diff --git a/test/CodeGen/AArch64/neon-shift-left-long.ll b/test/CodeGen/AArch64/neon-shift-left-long.ll
index d45c47685b0f4029ab544b9f7e2fea97660b0727..d10d551805a6b7d34f23727332286f5f204a7c40 100644 (file)
--- a/test/CodeGen/AArch64/neon-shift-left-long.ll
+++ b/test/CodeGen/AArch64/neon-shift-left-long.ll
@@ -191,3 +191,13 @@ define <2 x i64> @test_ushll2_shl0_v4i32(<4 x i32> %a) {
   %tmp = zext <2 x i32> %1 to <2 x i64>
   ret <2 x i64> %tmp
 }
+
+define <8 x i16> @test_ushll_cmp(<8 x i8> %a, <8 x i8> %b) #0 {
+; CHECK: test_ushll_cmp:
+; CHECK: cmeq  {{v[0-9]+}}.8b, {{v[0-9]+}}.8b, {{v[0-9]+}}.8b
+; CHECK-NEXT: ushll    {{v[0-9]+}}.8h, {{v[0-9]+}}.8b, #0
+  %cmp.i = icmp eq <8 x i8> %a, %b
+  %vcgtz.i.i = sext <8 x i1> %cmp.i to <8 x i8>
+  %vmovl.i.i.i = zext <8 x i8> %vcgtz.i.i to <8 x i16>
+  ret <8 x i16> %vmovl.i.i.i
+}