[llvm] bfca9a0 - [SystemZ] Fix the cost function for vector zero extend.

[Jonas Paulsson via llvm-commits]

Author: Jonas Paulsson
Date: 2022-06-21T16:42:05+02:00
New Revision: bfca9a0b991e33ff24a69835d7bb0e0985afc7bd

URL: https://github.com/llvm/llvm-project/commit/bfca9a0b991e33ff24a69835d7bb0e0985afc7bd
DIFF: https://github.com/llvm/llvm-project/commit/bfca9a0b991e33ff24a69835d7bb0e0985afc7bd.diff

LOG: [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

Added: 
    

Modified: 
    llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
    llvm/test/Analysis/CostModel/SystemZ/int-cast.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp b/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
index c06d43c4f7f22..69914049a00c3 100644
--- 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 59ad122e68711..4ab15c05edec3 100644
--- 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
 }