GlobalISel: Fix double count of offset for irregular vector breakdowns

Fixes cases with odd vectors that break into multiple requested size
pieces.

llvm-svn: 354280

Author: arsenm

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

@@ -1596,7 +1596,6 @@ LegalizerHelper::fewerElementsVectorBasic(MachineInstr &MI, unsigned TypeIdx,
       unsigned PartInsertReg = MRI.createGenericVirtualRegister(DstTy);
       MIRBuilder.buildInsert(PartInsertReg, AccumDstReg, PartDstReg, Offset);
       AccumDstReg = PartInsertReg;
-      Offset += NarrowSize;
     }
 
     // Handle the remaining element sized leftover piece.

llvm/unittests/CodeGen/GlobalISel/LegalizerHelperTest.cpp

@@ -547,4 +547,52 @@ TEST_F(GISelMITest, WidenUSUBO) {
   // Check
   EXPECT_TRUE(CheckMachineFunction(*MF, CheckStr)) << *MF;
 }
+
+TEST_F(GISelMITest, FewerElementsAnd) {
+  if (!TM)
+    return;
+
+  const LLT V2S32 = LLT::vector(2, 32);
+  const LLT V5S32 = LLT::vector(5, 32);
+
+  // Declare your legalization info
+  DefineLegalizerInfo(A, {
+    getActionDefinitionsBuilder(G_AND)
+      .legalFor({s32});
+  });
+
+  auto Op0 = B.buildUndef(V5S32);
+  auto Op1 = B.buildUndef(V5S32);
+  auto And = B.buildAnd(V5S32, Op0, Op1);
+
+  AInfo Info(MF->getSubtarget());
+  DummyGISelObserver Observer;
+  LegalizerHelper Helper(*MF, Info, Observer, B);
+  EXPECT_TRUE(Helper.fewerElementsVector(*And, 0, V2S32) ==
+              LegalizerHelper::LegalizeResult::Legalized);
+
+  auto CheckStr = R"(
+  CHECK: [[IMP_DEF0:%[0-9]+]]:_(<5 x s32>) = G_IMPLICIT_DEF
+  CHECK: [[IMP_DEF1:%[0-9]+]]:_(<5 x s32>) = G_IMPLICIT_DEF
+  CHECK: [[IMP_DEF2:%[0-9]+]]:_(<5 x s32>) = G_IMPLICIT_DEF
+  CHECK: [[EXTRACT0:%[0-9]+]]:_(<2 x s32>) = G_EXTRACT [[IMP_DEF0]]:_(<5 x s32>), 0
+  CHECK: [[EXTRACT1:%[0-9]+]]:_(<2 x s32>) = G_EXTRACT [[IMP_DEF1]]:_(<5 x s32>), 0
+  CHECK: [[AND0:%[0-9]+]]:_(<2 x s32>) = G_AND [[EXTRACT0]]:_, [[EXTRACT1]]:_
+  CHECK: [[INSERT0:%[0-9]+]]:_(<5 x s32>) = G_INSERT [[IMP_DEF2]]:_, [[AND0]]:_(<2 x s32>), 0
+
+  CHECK: [[EXTRACT2:%[0-9]+]]:_(<2 x s32>) = G_EXTRACT [[IMP_DEF0]]:_(<5 x s32>), 64
+  CHECK: [[EXTRACT3:%[0-9]+]]:_(<2 x s32>) = G_EXTRACT [[IMP_DEF1]]:_(<5 x s32>), 64
+  CHECK: [[AND1:%[0-9]+]]:_(<2 x s32>) = G_AND [[EXTRACT2]]:_, [[EXTRACT3]]:_
+  CHECK: [[INSERT1:%[0-9]+]]:_(<5 x s32>) = G_INSERT [[INSERT0]]:_, [[AND1]]:_(<2 x s32>), 64
+
+  CHECK: [[EXTRACT4:%[0-9]+]]:_(s32) = G_EXTRACT [[IMP_DEF0]]:_(<5 x s32>), 128
+  CHECK: [[EXTRACT5:%[0-9]+]]:_(s32) = G_EXTRACT [[IMP_DEF1]]:_(<5 x s32>), 128
+  CHECK: [[AND2:%[0-9]+]]:_(s32) = G_AND [[EXTRACT4]]:_, [[EXTRACT5]]:_
+  CHECK: [[INSERT2:%[0-9]+]]:_(<5 x s32>) = G_INSERT [[INSERT1]]:_, [[AND2]]:_(s32), 128
+  )";
+
+  // Check
+  EXPECT_TRUE(CheckMachineFunction(*MF, CheckStr)) << *MF;
+}
+
 } // namespace