[XCore] Provide information about known zero bits of resource instructions.

llvm-svn: 202393

1 files changed, 28 insertions, 0 deletions

diff --git a/llvm/lib/Target/XCore/XCoreISelLowering.cpp b/llvm/lib/Target/XCore/XCoreISelLowering.cpp
index 7af0165329f..930a4d19ba0 100644
--- a/llvm/lib/Target/XCore/XCoreISelLowering.cpp
+++ b/llvm/lib/Target/XCore/XCoreISelLowering.cpp
@@ -1770,6 +1770,34 @@ void XCoreTargetLowering::computeMaskedBitsForTargetNode(const SDValue Op,
                                         KnownZero.getBitWidth() - 1);
     }
     break;
+  case ISD::INTRINSIC_W_CHAIN:
+    {
+      unsigned IntNo = cast<ConstantSDNode>(Op.getOperand(1))->getZExtValue();
+      switch (IntNo) {
+      case Intrinsic::xcore_getts:
+        // High bits are known to be zero.
+        KnownZero = APInt::getHighBitsSet(KnownZero.getBitWidth(),
+                                          KnownZero.getBitWidth() - 16);
+        break;
+      case Intrinsic::xcore_int:
+      case Intrinsic::xcore_inct:
+        // High bits are known to be zero.
+        KnownZero = APInt::getHighBitsSet(KnownZero.getBitWidth(),
+                                          KnownZero.getBitWidth() - 8);
+        break;
+      case Intrinsic::xcore_testct:
+        // Result is either 0 or 1.
+        KnownZero = APInt::getHighBitsSet(KnownZero.getBitWidth(),
+                                          KnownZero.getBitWidth() - 1);
+        break;
+      case Intrinsic::xcore_testwct:
+        // Result is in the range 0 - 4.
+        KnownZero = APInt::getHighBitsSet(KnownZero.getBitWidth(),
+                                          KnownZero.getBitWidth() - 3);
+        break;
+      }
+    }
+    break;
   }
 }