[X86] Add a more accurate truncate cost for v8i64->v8i8

diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
index ad413a7..fc7c317 100644 (file)
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -1377,6 +1377,7 @@ int X86TTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src,
 
     { ISD::TRUNCATE,  MVT::v16i8,   MVT::v16i32, 1 },
     { ISD::TRUNCATE,  MVT::v16i16,  MVT::v16i32, 1 },
+    { ISD::TRUNCATE,  MVT::v8i8,    MVT::v8i64,  2 },
     { ISD::TRUNCATE,  MVT::v8i16,   MVT::v8i64,  1 },
     { ISD::TRUNCATE,  MVT::v8i32,   MVT::v8i64,  1 },
 

diff --git a/llvm/test/Analysis/CostModel/X86/min-legal-vector-width.ll b/llvm/test/Analysis/CostModel/X86/min-legal-vector-width.ll
index 8a4e774..d75e964 100644 (file)
--- a/llvm/test/Analysis/CostModel/X86/min-legal-vector-width.ll
+++ b/llvm/test/Analysis/CostModel/X86/min-legal-vector-width.ll
@@ -139,7 +139,7 @@ define void @trunc256() "min-legal-vector-width"="256" {
 ; VEC512-LABEL: 'trunc256'
 ; VEC512-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %A = trunc <8 x i64> undef to <8 x i32>
 ; VEC512-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %B = trunc <8 x i64> undef to <8 x i16>
-; VEC512-NEXT:  Cost Model: Found an estimated cost of 11 for instruction: %C = trunc <8 x i64> undef to <8 x i8>
+; VEC512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %C = trunc <8 x i64> undef to <8 x i8>
 ; VEC512-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %D = trunc <16 x i32> undef to <16 x i16>
 ; VEC512-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %E = trunc <16 x i32> undef to <16 x i8>
 ; VEC512-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %F = trunc <32 x i16> undef to <32 x i8>

diff --git a/llvm/test/Analysis/CostModel/X86/trunc.ll b/llvm/test/Analysis/CostModel/X86/trunc.ll
index d91c817..792310f 100644 (file)
--- a/llvm/test/Analysis/CostModel/X86/trunc.ll
+++ b/llvm/test/Analysis/CostModel/X86/trunc.ll
@@ -282,7 +282,7 @@ define i32 @trunc_vXi8() {
 ; AVX512F-LABEL: 'trunc_vXi8'
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2i64 = trunc <2 x i64> undef to <2 x i8>
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i64 = trunc <4 x i64> undef to <4 x i8>
-; AVX512F-NEXT:  Cost Model: Found an estimated cost of 11 for instruction: %V8i64 = trunc <8 x i64> undef to <8 x i8>
+; AVX512F-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8i64 = trunc <8 x i64> undef to <8 x i8>
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 11 for instruction: %V16i64 = trunc <16 x i64> undef to <16 x i8>
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V32i64 = trunc <32 x i64> undef to <32 x i8>
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V64i64 = trunc <64 x i64> undef to <64 x i8>
@@ -303,7 +303,7 @@ define i32 @trunc_vXi8() {
 ; AVX512BW-LABEL: 'trunc_vXi8'
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2i64 = trunc <2 x i64> undef to <2 x i8>
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i64 = trunc <4 x i64> undef to <4 x i8>
-; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 11 for instruction: %V8i64 = trunc <8 x i64> undef to <8 x i8>
+; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8i64 = trunc <8 x i64> undef to <8 x i8>
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 11 for instruction: %V16i64 = trunc <16 x i64> undef to <16 x i8>
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %V32i64 = trunc <32 x i64> undef to <32 x i8>
 ; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V64i64 = trunc <64 x i64> undef to <64 x i8>