[TargetLowering][RISCV] Allow scalable non-simple EVTs to be split even if the element type isn't a legal scalar type. (#144007)

This fixes an inconsistency in i64 vector handling between RV32 and
RV64. Even if i64 isn't legal as a scalar, we should still be able
to split a large i64 vector to get down to a legal vector type. We only
need to give up if we need to split a vscale x 1 vector.

Author: topperc

llvm/lib/CodeGen/TargetLoweringBase.cpp

@@ -1030,7 +1030,7 @@ TargetLoweringBase::getTypeConversion(LLVMContext &Context, EVT VT) const {
     // If type is to be expanded, split the vector.
     //  <4 x i140> -> <2 x i140>
     if (LK.first == TypeExpandInteger) {
-      if (VT.getVectorElementCount().isScalable())
+      if (NumElts.isScalable() && NumElts.getKnownMinValue() == 1)
         return LegalizeKind(TypeScalarizeScalableVector, EltVT);
       return LegalizeKind(TypeSplitVector,
                           VT.getHalfNumVectorElementsVT(Context));

llvm/test/Analysis/CostModel/RISCV/cast-half.ll

@@ -74,7 +74,7 @@ define void @fptosi() {
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 9 for instruction: %nxv64f16_nxv64i8 = fptosi <vscale x 64 x half> undef to <vscale x 64 x i8>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %nxv64f16_nxv64i16 = fptosi <vscale x 64 x half> undef to <vscale x 64 x i16>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 34 for instruction: %nxv64f16_nxv64i32 = fptosi <vscale x 64 x half> undef to <vscale x 64 x i32>
-; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 103 for instruction: %nxv64f16_nxv64i64 = fptosi <vscale x 64 x half> undef to <vscale x 64 x i64>
+; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 102 for instruction: %nxv64f16_nxv64i64 = fptosi <vscale x 64 x half> undef to <vscale x 64 x i64>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 25 for instruction: %nxv64f16_nxv64i1 = fptosi <vscale x 64 x half> undef to <vscale x 64 x i1>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
@@ -147,7 +147,7 @@ define void @fptosi() {
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 59 for instruction: %nxv64f16_nxv64i8 = fptosi <vscale x 64 x half> undef to <vscale x 64 x i8>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %nxv64f16_nxv64i16 = fptosi <vscale x 64 x half> undef to <vscale x 64 x i16>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 66 for instruction: %nxv64f16_nxv64i32 = fptosi <vscale x 64 x half> undef to <vscale x 64 x i32>
-; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 103 for instruction: %nxv64f16_nxv64i64 = fptosi <vscale x 64 x half> undef to <vscale x 64 x i64>
+; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 102 for instruction: %nxv64f16_nxv64i64 = fptosi <vscale x 64 x half> undef to <vscale x 64 x i64>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 83 for instruction: %nxv64f16_nxv64i1 = fptosi <vscale x 64 x half> undef to <vscale x 64 x i1>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
@@ -440,7 +440,7 @@ define void @fptoui() {
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 9 for instruction: %nxv64f16_nxv64i8 = fptoui <vscale x 64 x half> undef to <vscale x 64 x i8>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %nxv64f16_nxv64i16 = fptoui <vscale x 64 x half> undef to <vscale x 64 x i16>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 34 for instruction: %nxv64f16_nxv64i32 = fptoui <vscale x 64 x half> undef to <vscale x 64 x i32>
-; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 103 for instruction: %nxv64f16_nxv64i64 = fptoui <vscale x 64 x half> undef to <vscale x 64 x i64>
+; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 102 for instruction: %nxv64f16_nxv64i64 = fptoui <vscale x 64 x half> undef to <vscale x 64 x i64>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 25 for instruction: %nxv64f16_nxv64i1 = fptoui <vscale x 64 x half> undef to <vscale x 64 x i1>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
@@ -513,7 +513,7 @@ define void @fptoui() {
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 59 for instruction: %nxv64f16_nxv64i8 = fptoui <vscale x 64 x half> undef to <vscale x 64 x i8>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %nxv64f16_nxv64i16 = fptoui <vscale x 64 x half> undef to <vscale x 64 x i16>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 66 for instruction: %nxv64f16_nxv64i32 = fptoui <vscale x 64 x half> undef to <vscale x 64 x i32>
-; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 103 for instruction: %nxv64f16_nxv64i64 = fptoui <vscale x 64 x half> undef to <vscale x 64 x i64>
+; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 102 for instruction: %nxv64f16_nxv64i64 = fptoui <vscale x 64 x half> undef to <vscale x 64 x i64>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 83 for instruction: %nxv64f16_nxv64i1 = fptoui <vscale x 64 x half> undef to <vscale x 64 x i1>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
@@ -806,7 +806,7 @@ define void @sitofp() {
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 17 for instruction: %nxv64i8_nxv64f16 = sitofp <vscale x 64 x i8> undef to <vscale x 64 x half>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %nxv64i16_nxv64f16 = sitofp <vscale x 64 x i16> undef to <vscale x 64 x half>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 18 for instruction: %nxv64i32_nxv64f16 = sitofp <vscale x 64 x i32> undef to <vscale x 64 x half>
-; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 55 for instruction: %nxv64i64_nxv64f16 = sitofp <vscale x 64 x i64> undef to <vscale x 64 x half>
+; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 54 for instruction: %nxv64i64_nxv64f16 = sitofp <vscale x 64 x i64> undef to <vscale x 64 x half>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 33 for instruction: %nxv64i1_nxv64f16 = sitofp <vscale x 64 x i1> undef to <vscale x 64 x half>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
@@ -879,7 +879,7 @@ define void @sitofp() {
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 83 for instruction: %nxv64i8_nxv64f16 = sitofp <vscale x 64 x i8> undef to <vscale x 64 x half>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %nxv64i16_nxv64f16 = sitofp <vscale x 64 x i16> undef to <vscale x 64 x half>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 50 for instruction: %nxv64i32_nxv64f16 = sitofp <vscale x 64 x i32> undef to <vscale x 64 x half>
-; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 55 for instruction: %nxv64i64_nxv64f16 = sitofp <vscale x 64 x i64> undef to <vscale x 64 x half>
+; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 54 for instruction: %nxv64i64_nxv64f16 = sitofp <vscale x 64 x i64> undef to <vscale x 64 x half>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 99 for instruction: %nxv64i1_nxv64f16 = sitofp <vscale x 64 x i1> undef to <vscale x 64 x half>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
@@ -1172,7 +1172,7 @@ define void @uitofp() {
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 17 for instruction: %nxv64i8_nxv64f16 = uitofp <vscale x 64 x i8> undef to <vscale x 64 x half>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %nxv64i16_nxv64f16 = uitofp <vscale x 64 x i16> undef to <vscale x 64 x half>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 18 for instruction: %nxv64i32_nxv64f16 = uitofp <vscale x 64 x i32> undef to <vscale x 64 x half>
-; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 55 for instruction: %nxv64i64_nxv64f16 = uitofp <vscale x 64 x i64> undef to <vscale x 64 x half>
+; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 54 for instruction: %nxv64i64_nxv64f16 = uitofp <vscale x 64 x i64> undef to <vscale x 64 x half>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 33 for instruction: %nxv64i1_nxv64f16 = uitofp <vscale x 64 x i1> undef to <vscale x 64 x half>
 ; RV32ZVFH-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
@@ -1245,7 +1245,7 @@ define void @uitofp() {
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 83 for instruction: %nxv64i8_nxv64f16 = uitofp <vscale x 64 x i8> undef to <vscale x 64 x half>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %nxv64i16_nxv64f16 = uitofp <vscale x 64 x i16> undef to <vscale x 64 x half>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 50 for instruction: %nxv64i32_nxv64f16 = uitofp <vscale x 64 x i32> undef to <vscale x 64 x half>
-; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 55 for instruction: %nxv64i64_nxv64f16 = uitofp <vscale x 64 x i64> undef to <vscale x 64 x half>
+; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 54 for instruction: %nxv64i64_nxv64f16 = uitofp <vscale x 64 x i64> undef to <vscale x 64 x half>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 99 for instruction: %nxv64i1_nxv64f16 = uitofp <vscale x 64 x i1> undef to <vscale x 64 x half>
 ; RV32ZVFHMIN-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;