[Vectorizer] Add a new 'OperandValueKind' in TargetTransformInfo called

'OK_NonUniformConstValue' to identify operands which are constants but
not constant splats.

The cost model now allows returning 'OK_NonUniformConstValue'
for non splat operands that are instances of ConstantVector or
ConstantDataVector.

With this change, targets are now able to compute different costs
for instructions with non-uniform constant operands.
For example, On X86 the cost of a vector shift may vary depending on whether
the second operand is a uniform or non-uniform constant.

This patch applies the following changes:
 - The cost model computation now takes into account non-uniform constants;
 - The cost of vector shift instructions has been improved in
   X86TargetTransformInfo analysis pass;
 - BBVectorize, SLPVectorizer and LoopVectorize now know how to distinguish
   between non-uniform and uniform constant operands.

Added a new test to verify that the output of opt
'-cost-model -analyze' is valid in the following configurations: SSE2,
SSE4.1, AVX, AVX2.

llvm-svn: 201272

1 files changed, 8 insertions, 3 deletions

diff --git a/llvm/lib/Analysis/CostModel.cpp b/llvm/lib/Analysis/CostModel.cpp
index 543977a376f..898da8d0e8d 100644
--- a/llvm/lib/Analysis/CostModel.cpp
+++ b/llvm/lib/Analysis/CostModel.cpp
@@ -98,15 +98,20 @@ static TargetTransformInfo::OperandValueKind getOperandInfo(Value *V) {
   TargetTransformInfo::OperandValueKind OpInfo =
     TargetTransformInfo::OK_AnyValue;
 
-  // Check for a splat of a constant.
+  // Check for a splat of a constant or for a non uniform vector of constants.
   ConstantDataVector *CDV = 0;
-  if ((CDV = dyn_cast<ConstantDataVector>(V)))
+  if ((CDV = dyn_cast<ConstantDataVector>(V))) {
+    OpInfo = TargetTransformInfo::OK_NonUniformConstantValue;
     if (CDV->getSplatValue() != NULL)
       OpInfo = TargetTransformInfo::OK_UniformConstantValue;
+  }
+
   ConstantVector *CV = 0;
-  if ((CV = dyn_cast<ConstantVector>(V)))
+  if ((CV = dyn_cast<ConstantVector>(V))) {
+    OpInfo = TargetTransformInfo::OK_NonUniformConstantValue;
     if (CV->getSplatValue() != NULL)
       OpInfo = TargetTransformInfo::OK_UniformConstantValue;
+  }
 
   return OpInfo;
 }