[llvm-commits] [llvm] r163203 - in /llvm/trunk: lib/CodeGen/SelectionDAG/DAGCombiner.cpp test/CodeGen/ARM/vector-extend-narrow.ll

[Silviu Baranga]

Author: sbaranga
Date: Wed Sep  5 03:57:21 2012
New Revision: 163203

URL: http://llvm.org/viewvc/llvm-project?rev=163203&view=rev
Log:
Fixed the DAG combiner to better handle the folding of AND nodes for vector types. The previous code was making the assumption that the length of the bitmask returned by isConstantSplat was equal to the size of the vector type. Now we first make sure that the splat value has at least the length of the vector lane type, then we only use as many fields as we have available in the splat value.

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
    llvm/trunk/test/CodeGen/ARM/vector-extend-narrow.ll

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=163203&r1=163202&r2=163203&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Wed Sep  5 03:57:21 2012
@@ -2496,8 +2496,18 @@
         // lanes of the constant together.
         EVT VT = Vector->getValueType(0);
         unsigned BitWidth = VT.getVectorElementType().getSizeInBits();
+
+        // If the splat value has been compressed to a bitlength lower
+        // than the size of the vector lane, we need to re-expand it to
+        // the lane size.
+        if (BitWidth > SplatBitSize)
+          for (SplatValue = SplatValue.zextOrTrunc(BitWidth);
+               SplatBitSize < BitWidth;
+               SplatBitSize = SplatBitSize * 2)
+            SplatValue |= SplatValue.shl(SplatBitSize);
+
         Constant = APInt::getAllOnesValue(BitWidth);
-        for (unsigned i = 0, n = VT.getVectorNumElements(); i < n; ++i)
+        for (unsigned i = 0, n = SplatBitSize/BitWidth; i < n; ++i)
           Constant &= SplatValue.lshr(i*BitWidth).zextOrTrunc(BitWidth);
       }
     }

Modified: llvm/trunk/test/CodeGen/ARM/vector-extend-narrow.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/vector-extend-narrow.ll?rev=163203&r1=163202&r2=163203&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/vector-extend-narrow.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/vector-extend-narrow.ll Wed Sep  5 03:57:21 2012
@@ -62,3 +62,14 @@
   %2 = sdiv <4 x i8> zeroinitializer, %1
   ret <4 x i8> %2
 }
+; CHECK: j:
+define <4 x i32> @j(<4 x i8>* %in) nounwind {
+  ; CHECK: vld1
+  ; CHECK: vmovl.u8
+  ; CHECK: vmovl.u16
+  ; CHECK-NOT: vand
+  %1 = load <4 x i8>* %in, align 4
+  %2 = zext <4 x i8> %1 to <4 x i32>
+  ret <4 x i32> %2
+}
+