[llvm-commits] [llvm-gcc-4.2] r84678 - /llvm-gcc-4.2/trunk/gcc/config/arm/llvm-arm.cpp

[Bob Wilson]

Author: bwilson
Date: Tue Oct 20 16:08:21 2009
New Revision: 84678

URL: http://llvm.org/viewvc/llvm-project?rev=84678&view=rev
Log:
Translate NEON vget_high and vget_low builtins to extract_element with a
v2f64 type instead of using vector shuffles.  The code generator does not
produce good code for a shuffle where the inputs have more elements than
the result.

Modified:
    llvm-gcc-4.2/trunk/gcc/config/arm/llvm-arm.cpp

Modified: llvm-gcc-4.2/trunk/gcc/config/arm/llvm-arm.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm-gcc-4.2/trunk/gcc/config/arm/llvm-arm.cpp?rev=84678&r1=84677&r2=84678&view=diff

==============================================================================
--- llvm-gcc-4.2/trunk/gcc/config/arm/llvm-arm.cpp (original)
+++ llvm-gcc-4.2/trunk/gcc/config/arm/llvm-arm.cpp Tue Oct 20 16:08:21 2009
@@ -1690,14 +1690,11 @@
 
   case NEON_BUILTIN_vget_high:
   case NEON_BUILTIN_vget_low: {
-    unsigned NUnits = GET_MODE_NUNITS(insn_data[icode].operand[0].mode);
-    std::vector<Constant*> Idxs;
-    unsigned Idx = (neon_code == NEON_BUILTIN_vget_low ? 0 : NUnits);
-    for (unsigned i = 0; i != NUnits; ++i)
-      Idxs.push_back(getInt32Const(Idx++));
-    Result = Builder.CreateShuffleVector(Ops[0],
-                                         UndefValue::get(Ops[0]->getType()),
-                                         ConstantVector::get(Idxs));
+    const Type *v2f64Ty = VectorType::get(Type::getDoubleTy(Context), 2);
+    unsigned Idx = (neon_code == NEON_BUILTIN_vget_low ? 0 : 1);
+    Result = Builder.CreateBitCast(Ops[0], v2f64Ty);
+    Result = Builder.CreateExtractElement(Result, getInt32Const(Idx));
+    Result = Builder.CreateBitCast(Result, ResultType);
     break;
   }