[CostModel][X86] getShuffleCost - use processShuffleMasks for all shuffle kinds to legal types (#120599) (#121760)

Now that processShuffleMasks can correctly handle 2 src shuffles, we can completely remove the shuffle kind limits and correctly recognize the number of active subvectors per legalized shuffle - improveShuffleKindFromMask will determine the shuffle kind for each split subvector.

Author: RKSimon

llvm/lib/Target/X86/X86TargetTransformInfo.cpp

@@ -1698,8 +1698,7 @@ InstructionCost X86TTIImpl::getShuffleCost(
   // We are going to permute multiple sources and the result will be in multiple
   // destinations. Providing an accurate cost only for splits where the element
   // type remains the same.
-  if ((Kind == TTI::SK_PermuteSingleSrc || Kind == TTI::SK_PermuteTwoSrc) &&
-      LT.first != 1) {
+  if (LT.first != 1) {
     MVT LegalVT = LT.second;
     if (LegalVT.isVector() &&
         LegalVT.getVectorElementType().getSizeInBits() ==

llvm/test/Analysis/CostModel/X86/alternate-shuffle-cost.ll

@@ -294,13 +294,9 @@ define <4 x i64> @test_v4i64_2(<4 x i64> %a, <4 x i64> %b) {
 }
 
 define <4 x i64> @test_v4i64_3(<4 x i64> %a, <4 x i64> %b) {
-; SSE-LABEL: 'test_v4i64_3'
-; SSE-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %1 = shufflevector <4 x i64> %a, <4 x i64> %b, <4 x i32> <i32 4, i32 1, i32 2, i32 3>
-; SSE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x i64> %1
-;
-; AVX-LABEL: 'test_v4i64_3'
-; AVX-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %1 = shufflevector <4 x i64> %a, <4 x i64> %b, <4 x i32> <i32 4, i32 1, i32 2, i32 3>
-; AVX-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x i64> %1
+; CHECK-LABEL: 'test_v4i64_3'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %1 = shufflevector <4 x i64> %a, <4 x i64> %b, <4 x i32> <i32 4, i32 1, i32 2, i32 3>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x i64> %1
 ;
   %1 = shufflevector <4 x i64> %a, <4 x i64> %b, <4 x i32> <i32 4, i32 1, i32 2, i32 3>
   ret <4 x i64> %1
@@ -333,13 +329,9 @@ define <4 x double> @test_v4f64_2(<4 x double> %a, <4 x double> %b) {
 }
 
 define <4 x double> @test_v4f64_3(<4 x double> %a, <4 x double> %b) {
-; SSE-LABEL: 'test_v4f64_3'
-; SSE-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %1 = shufflevector <4 x double> %a, <4 x double> %b, <4 x i32> <i32 4, i32 5, i32 6, i32 3>
-; SSE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x double> %1
-;
-; AVX-LABEL: 'test_v4f64_3'
-; AVX-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %1 = shufflevector <4 x double> %a, <4 x double> %b, <4 x i32> <i32 4, i32 5, i32 6, i32 3>
-; AVX-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x double> %1
+; CHECK-LABEL: 'test_v4f64_3'
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %1 = shufflevector <4 x double> %a, <4 x double> %b, <4 x i32> <i32 4, i32 5, i32 6, i32 3>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret <4 x double> %1
 ;
   %1 = shufflevector <4 x double> %a, <4 x double> %b, <4 x i32> <i32 4, i32 5, i32 6, i32 3>
   ret <4 x double> %1