[llvm-commits] [llvm] r80935 - /llvm/trunk/lib/Target/X86/X86ISelLowering.cpp

[Mon P Wang]

Author: wangmp
Date: Thu Sep  3 14:56:25 2009
New Revision: 80935

URL: http://llvm.org/viewvc/llvm-project?rev=80935&view=rev
Log:
Fixed a few problems with vector shifts
  - when transforming a vector shift of a non-immediate scalar shift amount, zero
    extend the i32 shift amount to i64 since the vector shift reads 64 bits
  - when transforming i16 vectors to use a vector shift, zero extend i16 shift amount
  - improve the code quality in some cases when transforming vectors to use a vector shift


Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=80935&r1=80934&r2=80935&view=diff

==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Thu Sep  3 14:56:25 2009
@@ -6359,9 +6359,23 @@
       break;
     }
     }
+
+    // The vector shift intrinsics with scalars uses 32b shift amounts but
+    // the sse2/mmx shift instructions reads 64 bits. Set the upper 32 bits
+    // to be zero.
+    SDValue ShOps[4];
+    ShOps[0] = ShAmt;
+    ShOps[1] = DAG.getConstant(0, MVT::i32);
+    if (ShAmtVT == MVT::v4i32) {
+      ShOps[2] = DAG.getUNDEF(MVT::i32);
+      ShOps[3] = DAG.getUNDEF(MVT::i32);
+      ShAmt =  DAG.getNode(ISD::BUILD_VECTOR, dl, ShAmtVT, &ShOps[0], 4);
+    } else {
+      ShAmt =  DAG.getNode(ISD::BUILD_VECTOR, dl, ShAmtVT, &ShOps[0], 2);
+    }
+
     EVT VT = Op.getValueType();
-    ShAmt = DAG.getNode(ISD::BIT_CONVERT, dl, VT,
-                        DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, ShAmtVT, ShAmt));
+    ShAmt = DAG.getNode(ISD::BIT_CONVERT, dl, VT, ShAmt);
     return DAG.getNode(ISD::INTRINSIC_WO_CHAIN, dl, VT,
                        DAG.getConstant(NewIntNo, MVT::i32),
                        Op.getOperand(1), ShAmt);
@@ -8554,7 +8568,7 @@
   SDValue ShAmtOp = N->getOperand(1);
   EVT EltVT = VT.getVectorElementType();
   DebugLoc DL = N->getDebugLoc();
-  SDValue BaseShAmt;
+  SDValue BaseShAmt = SDValue();
   if (ShAmtOp.getOpcode() == ISD::BUILD_VECTOR) {
     unsigned NumElts = VT.getVectorNumElements();
     unsigned i = 0;
@@ -8573,15 +8587,34 @@
     }
   } else if (ShAmtOp.getOpcode() == ISD::VECTOR_SHUFFLE &&
              cast<ShuffleVectorSDNode>(ShAmtOp)->isSplat()) {
-    BaseShAmt = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, EltVT, ShAmtOp,
-                            DAG.getIntPtrConstant(0));
+    SDValue InVec = ShAmtOp.getOperand(0);
+    if (InVec.getOpcode() == ISD::BUILD_VECTOR) {
+      unsigned NumElts = InVec.getValueType().getVectorNumElements();
+      unsigned i = 0;
+      for (; i != NumElts; ++i) {
+        SDValue Arg = InVec.getOperand(i);
+        if (Arg.getOpcode() == ISD::UNDEF) continue;
+        BaseShAmt = Arg;
+        break;
+      }
+    } else if (InVec.getOpcode() == ISD::INSERT_VECTOR_ELT) {
+       if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(InVec.getOperand(2))) {
+         unsigned SplatIdx = cast<ShuffleVectorSDNode>(ShAmtOp)->getSplatIndex();
+         if (C->getZExtValue() == SplatIdx)
+           BaseShAmt = InVec.getOperand(1);
+       }
+    }
+    if (BaseShAmt.getNode() == 0)
+      BaseShAmt = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, EltVT, ShAmtOp,
+                              DAG.getIntPtrConstant(0));
   } else
     return SDValue();
 
+  // The shift amount is an i32.
   if (EltVT.bitsGT(MVT::i32))
     BaseShAmt = DAG.getNode(ISD::TRUNCATE, DL, MVT::i32, BaseShAmt);
   else if (EltVT.bitsLT(MVT::i32))
-    BaseShAmt = DAG.getNode(ISD::ANY_EXTEND, DL, MVT::i32, BaseShAmt);
+    BaseShAmt = DAG.getNode(ISD::ZERO_EXTEND, DL, MVT::i32, BaseShAmt);
 
   // The shift amount is identical so we can do a vector shift.
   SDValue  ValOp = N->getOperand(0);