[AArch64] Fix PRR33100.

This commit fixes a bug introduced in r301019 where optimizeLogicalImm
would replace a logical node's immediate operand that was CSE'd and
was also an operand of another node.

This commit fixes the bug by replacing the logical node instead of its
immediate operand.

rdar://problem/32295276

llvm-svn: 303607

2 files changed, 29 insertions, 7 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index 1af36086ad9..5b8c645f824 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -886,18 +886,21 @@ static bool optimizeLogicalImm(SDValue Op, unsigned Size, uint64_t Imm,
   // Create the new constant immediate node.
   EVT VT = Op.getValueType();
   SDLoc DL(Op);
+  SDValue New;
 
   // If the new constant immediate is all-zeros or all-ones, let the target
   // independent DAG combine optimize this node.
-  if (NewImm == 0 || NewImm == OrigMask)
-    return TLO.CombineTo(Op.getOperand(1), TLO.DAG.getConstant(NewImm, DL, VT));
-
+  if (NewImm == 0 || NewImm == OrigMask) {
+    New = TLO.DAG.getNode(Op.getOpcode(), DL, VT, Op.getOperand(0),
+                          TLO.DAG.getConstant(NewImm, DL, VT));
   // Otherwise, create a machine node so that target independent DAG combine
   // doesn't undo this optimization.
-  Enc = AArch64_AM::encodeLogicalImmediate(NewImm, Size);
-  SDValue EncConst = TLO.DAG.getTargetConstant(Enc, DL, VT);
-  SDValue New(
-      TLO.DAG.getMachineNode(NewOpc, DL, VT, Op.getOperand(0), EncConst), 0);
+  } else {
+    Enc = AArch64_AM::encodeLogicalImmediate(NewImm, Size);
+    SDValue EncConst = TLO.DAG.getTargetConstant(Enc, DL, VT);
+    New = SDValue(
+        TLO.DAG.getMachineNode(NewOpc, DL, VT, Op.getOperand(0), EncConst), 0);
+  }
 
   return TLO.CombineTo(Op, New);
 }
diff --git a/llvm/test/CodeGen/AArch64/optimize-imm.ll b/llvm/test/CodeGen/AArch64/optimize-imm.ll
index a4725c65aa2..f960a3a95fc 100644
--- a/llvm/test/CodeGen/AArch64/optimize-imm.ll
+++ b/llvm/test/CodeGen/AArch64/optimize-imm.ll
@@ -62,3 +62,22 @@ entry:
   %and = xor i32 %xor, 56
   ret i32 %and
 }
+
+; Check that, when (and %t1, 129) is transformed to (and %t0, 0),
+; (xor %arg, 129) doesn't get transformed to (xor %arg, 0).
+;
+; CHECK-LABEL: PR33100:
+; CHECK: mov w[[R0:[0-9]+]], #129
+; CHECK: eor {{x[0-9]+}}, {{x[0-9]+}}, x[[R0]]
+
+define i64 @PR33100(i64 %arg) {
+entry:
+  %alloca0 = alloca i64
+  store i64 8, i64* %alloca0, align 4
+  %t0 = load i64, i64* %alloca0, align 4
+  %t1 = shl i64 %arg, %t0
+  %and0 = and i64 %t1, 129
+  %xor0 = xor i64 %arg, 129
+  %t2 = add i64 %and0, %xor0
+  ret i64 %t2
+}