[SystemZ] Fix the cost function for vector zero extend.

Zero extend of a vector is done with either a single unpack or a vector
permute, and the TTI cost function should reflect this.

Review: Ulrich Weigand

diff --git a/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp b/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
index c06d43c..6991404 100644 (file)
--- a/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
@@ -818,7 +818,11 @@ InstructionCost SystemZTTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst,
 
     if (Opcode == Instruction::ZExt || Opcode == Instruction::SExt) {
       if (SrcScalarBits >= 8) {
-        // ZExt/SExt will be handled with one unpack per doubling of width.
+        // ZExt will use either a single unpack or a vector permute.
+        if (Opcode == Instruction::ZExt)
+          return NumDstVectors;
+
+        // SExt will be handled with one unpack per doubling of width.
         unsigned NumUnpacks = getElSizeLog2Diff(Src, Dst);
 
         // For types that spans multiple vector registers, some additional

diff --git a/llvm/test/Analysis/CostModel/SystemZ/int-cast.ll b/llvm/test/Analysis/CostModel/SystemZ/int-cast.ll
index 59ad122..4ab15c0 100644 (file)
--- a/llvm/test/Analysis/CostModel/SystemZ/int-cast.ll
+++ b/llvm/test/Analysis/CostModel/SystemZ/int-cast.ll
@@ -105,29 +105,29 @@ define void @zext() {
 ; CHECK: Cost Model: Found an estimated cost of 1 for instruction:   %v4 = zext i16 undef to i64
 ; CHECK: Cost Model: Found an estimated cost of 1 for instruction:   %v5 = zext i32 undef to i64
 ; CHECK: Cost Model: Found an estimated cost of 1 for instruction:   %v6 = zext <2 x i8> undef to <2 x i16>
-; CHECK: Cost Model: Found an estimated cost of 2 for instruction:   %v7 = zext <2 x i8> undef to <2 x i32>
-; CHECK: Cost Model: Found an estimated cost of 3 for instruction:   %v8 = zext <2 x i8> undef to <2 x i64>
+; CHECK: Cost Model: Found an estimated cost of 1 for instruction:   %v7 = zext <2 x i8> undef to <2 x i32>
+; CHECK: Cost Model: Found an estimated cost of 1 for instruction:   %v8 = zext <2 x i8> undef to <2 x i64>
 ; CHECK: Cost Model: Found an estimated cost of 1 for instruction:   %v9 = zext <2 x i16> undef to <2 x i32>
-; CHECK: Cost Model: Found an estimated cost of 2 for instruction:   %v10 = zext <2 x i16> undef to <2 x i64>
+; CHECK: Cost Model: Found an estimated cost of 1 for instruction:   %v10 = zext <2 x i16> undef to <2 x i64>
 ; CHECK: Cost Model: Found an estimated cost of 1 for instruction:   %v11 = zext <2 x i32> undef to <2 x i64>
 ; CHECK: Cost Model: Found an estimated cost of 1 for instruction:   %v12 = zext <4 x i8> undef to <4 x i16>
-; CHECK: Cost Model: Found an estimated cost of 2 for instruction:   %v13 = zext <4 x i8> undef to <4 x i32>
-; CHECK: Cost Model: Found an estimated cost of 7 for instruction:   %v14 = zext <4 x i8> undef to <4 x i64>
+; CHECK: Cost Model: Found an estimated cost of 1 for instruction:   %v13 = zext <4 x i8> undef to <4 x i32>
+; CHECK: Cost Model: Found an estimated cost of 2 for instruction:   %v14 = zext <4 x i8> undef to <4 x i64>
 ; CHECK: Cost Model: Found an estimated cost of 1 for instruction:   %v15 = zext <4 x i16> undef to <4 x i32>
-; CHECK: Cost Model: Found an estimated cost of 5 for instruction:   %v16 = zext <4 x i16> undef to <4 x i64>
-; CHECK: Cost Model: Found an estimated cost of 3 for instruction:   %v17 = zext <4 x i32> undef to <4 x i64>
+; CHECK: Cost Model: Found an estimated cost of 2 for instruction:   %v16 = zext <4 x i16> undef to <4 x i64>
+; CHECK: Cost Model: Found an estimated cost of 2 for instruction:   %v17 = zext <4 x i32> undef to <4 x i64>
 ; CHECK: Cost Model: Found an estimated cost of 1 for instruction:   %v18 = zext <8 x i8> undef to <8 x i16>
-; CHECK: Cost Model: Found an estimated cost of 5 for instruction:   %v19 = zext <8 x i8> undef to <8 x i32>
-; CHECK: Cost Model: Found an estimated cost of 15 for instruction:   %v20 = zext <8 x i8> undef to <8 x i64>
-; CHECK: Cost Model: Found an estimated cost of 3 for instruction:   %v21 = zext <8 x i16> undef to <8 x i32>
-; CHECK: Cost Model: Found an estimated cost of 11 for instruction:   %v22 = zext <8 x i16> undef to <8 x i64>
-; CHECK: Cost Model: Found an estimated cost of 6 for instruction:   %v23 = zext <8 x i32> undef to <8 x i64>
-; CHECK: Cost Model: Found an estimated cost of 3 for instruction:   %v24 = zext <16 x i8> undef to <16 x i16>
-; CHECK: Cost Model: Found an estimated cost of 11 for instruction:   %v25 = zext <16 x i8> undef to <16 x i32>
-; CHECK: Cost Model: Found an estimated cost of 31 for instruction:   %v26 = zext <16 x i8> undef to <16 x i64>
-; CHECK: Cost Model: Found an estimated cost of 6 for instruction:   %v27 = zext <16 x i16> undef to <16 x i32>
-; CHECK: Cost Model: Found an estimated cost of 22 for instruction:   %v28 = zext <16 x i16> undef to <16 x i64>
-; CHECK: Cost Model: Found an estimated cost of 12 for instruction:   %v29 = zext <16 x i32> undef to <16 x i64>
+; CHECK: Cost Model: Found an estimated cost of 2 for instruction:   %v19 = zext <8 x i8> undef to <8 x i32>
+; CHECK: Cost Model: Found an estimated cost of 4 for instruction:   %v20 = zext <8 x i8> undef to <8 x i64>
+; CHECK: Cost Model: Found an estimated cost of 2 for instruction:   %v21 = zext <8 x i16> undef to <8 x i32>
+; CHECK: Cost Model: Found an estimated cost of 4 for instruction:   %v22 = zext <8 x i16> undef to <8 x i64>
+; CHECK: Cost Model: Found an estimated cost of 4 for instruction:   %v23 = zext <8 x i32> undef to <8 x i64>
+; CHECK: Cost Model: Found an estimated cost of 2 for instruction:   %v24 = zext <16 x i8> undef to <16 x i16>
+; CHECK: Cost Model: Found an estimated cost of 4 for instruction:   %v25 = zext <16 x i8> undef to <16 x i32>
+; CHECK: Cost Model: Found an estimated cost of 8 for instruction:   %v26 = zext <16 x i8> undef to <16 x i64>
+; CHECK: Cost Model: Found an estimated cost of 4 for instruction:   %v27 = zext <16 x i16> undef to <16 x i32>
+; CHECK: Cost Model: Found an estimated cost of 8 for instruction:   %v28 = zext <16 x i16> undef to <16 x i64>
+; CHECK: Cost Model: Found an estimated cost of 8 for instruction:   %v29 = zext <16 x i32> undef to <16 x i64>
 
  ret void
 }