[llvm] [RISCV] Change vector tuple type's TypeSize to scalable (PR #114329)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-risc-v

Author: Brandon Wu (4vtomat)

<details>
<summary>Changes</summary>

Vector tuple is basically multiple grouped vector, so its size is also
determined by vscale, we need not to model it as a vector type but its
size need to be scalable.


---
Full diff: https://github.com/llvm/llvm-project/pull/114329.diff


4 Files Affected:

- (modified) llvm/include/llvm/CodeGen/ValueTypes.td (+1) 
- (modified) llvm/lib/CodeGen/ValueTypes.cpp (+1-1) 
- (modified) llvm/lib/CodeGenTypes/LowLevelType.cpp (+5) 
- (modified) llvm/lib/Target/RISCV/RISCVISelLowering.cpp (+27-20) 


``````````diff
diff --git a/llvm/include/llvm/CodeGen/ValueTypes.td b/llvm/include/llvm/CodeGen/ValueTypes.td
index 6d6b92958b4321..ee1b31703e12b9 100644
--- a/llvm/include/llvm/CodeGen/ValueTypes.td
+++ b/llvm/include/llvm/CodeGen/ValueTypes.td
@@ -63,6 +63,7 @@ class VTVecTup<int size, int nf, ValueType dummy_elt, int value>
   let NF = nf;
   let ElementType = dummy_elt;
   let isRISCVVecTuple = true;
+  let isScalable = true;
 }
 
 defset list<ValueType> ValueTypes = {
diff --git a/llvm/lib/CodeGen/ValueTypes.cpp b/llvm/lib/CodeGen/ValueTypes.cpp
index e3c746b274dde1..2c80eee7c904c1 100644
--- a/llvm/lib/CodeGen/ValueTypes.cpp
+++ b/llvm/lib/CodeGen/ValueTypes.cpp
@@ -163,7 +163,7 @@ std::string EVT::getEVTString() const {
   switch (V.SimpleTy) {
   default:
     if (isRISCVVectorTuple()) {
-      unsigned Sz = getSizeInBits();
+      unsigned Sz = getSizeInBits().getKnownMinValue();
       unsigned NF = getRISCVVectorTupleNumFields();
       unsigned MinNumElts = Sz / (NF * 8);
       return "riscv_nxv" + utostr(MinNumElts) + "i8x" + utostr(NF);
diff --git a/llvm/lib/CodeGenTypes/LowLevelType.cpp b/llvm/lib/CodeGenTypes/LowLevelType.cpp
index 5530a2ea952dd9..a798d8855a4636 100644
--- a/llvm/lib/CodeGenTypes/LowLevelType.cpp
+++ b/llvm/lib/CodeGenTypes/LowLevelType.cpp
@@ -22,6 +22,11 @@ LLT::LLT(MVT VT) {
     init(/*IsPointer=*/false, asVector, /*IsScalar=*/!asVector,
          VT.getVectorElementCount(), VT.getVectorElementType().getSizeInBits(),
          /*AddressSpace=*/0);
+  } else if (VT.isRISCVVectorTuple()) {
+    // TODO: Correctly model RISC-V vector tuple type
+    init(/*IsPointer=*/false, /*IsVector=*/false, /*IsScalar=*/true,
+         ElementCount::getFixed(0), VT.getSizeInBits().getKnownMinValue(),
+         /*AddressSpace=*/0);
   } else if (VT.isValid() && !VT.isScalableTargetExtVT()) {
     // Aggregates are no different from real scalars as far as GlobalISel is
     // concerned.
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index af7a39b2580a37..210657a7481d08 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -2416,8 +2416,9 @@ unsigned RISCVTargetLowering::getSubregIndexByMVT(MVT VT, unsigned Index) {
 unsigned RISCVTargetLowering::getRegClassIDForVecVT(MVT VT) {
   if (VT.isRISCVVectorTuple()) {
     unsigned NF = VT.getRISCVVectorTupleNumFields();
-    unsigned RegsPerField = std::max(1U, (unsigned)VT.getSizeInBits() /
-                                             (NF * RISCV::RVVBitsPerBlock));
+    unsigned RegsPerField =
+        std::max(1U, (unsigned)VT.getSizeInBits().getKnownMinValue() /
+                         (NF * RISCV::RVVBitsPerBlock));
     switch (RegsPerField) {
     case 1:
       if (NF == 2)
@@ -7006,7 +7007,7 @@ SDValue RISCVTargetLowering::LowerOperation(SDValue Op,
       SDLoc DL(Op);
       MVT XLenVT = Subtarget.getXLenVT();
       unsigned NF = VecTy.getRISCVVectorTupleNumFields();
-      unsigned Sz = VecTy.getSizeInBits();
+      unsigned Sz = VecTy.getSizeInBits().getKnownMinValue();
       unsigned NumElts = Sz / (NF * 8);
       int Log2LMUL = Log2_64(NumElts) - 3;
 
@@ -7049,7 +7050,7 @@ SDValue RISCVTargetLowering::LowerOperation(SDValue Op,
       SDLoc DL(Op);
       MVT XLenVT = Subtarget.getXLenVT();
       unsigned NF = VecTy.getRISCVVectorTupleNumFields();
-      unsigned Sz = VecTy.getSizeInBits();
+      unsigned Sz = VecTy.getSizeInBits().getKnownMinValue();
       unsigned NumElts = Sz / (NF * 8);
       int Log2LMUL = Log2_64(NumElts) - 3;
 
@@ -21309,6 +21310,25 @@ bool RISCVTargetLowering::splitValueIntoRegisterParts(
     return true;
   }
 
+  if (ValueVT.isRISCVVectorTuple() && PartVT.isRISCVVectorTuple()) {
+    unsigned ValNF = ValueVT.getRISCVVectorTupleNumFields();
+    [[maybe_unused]] unsigned ValLMUL =
+        divideCeil(ValueVT.getSizeInBits().getKnownMinValue(),
+                   ValNF * RISCV::RVVBitsPerBlock);
+    unsigned PartNF = PartVT.getRISCVVectorTupleNumFields();
+    [[maybe_unused]] unsigned PartLMUL =
+        divideCeil(PartVT.getSizeInBits().getKnownMinValue(),
+                   PartNF * RISCV::RVVBitsPerBlock);
+    assert(ValNF == PartNF && ValLMUL == PartLMUL &&
+           "RISC-V vector tuple type only accepts same register class type "
+           "TUPLE_INSERT");
+
+    Val = DAG.getNode(RISCVISD::TUPLE_INSERT, DL, PartVT, DAG.getUNDEF(PartVT),
+                      Val, DAG.getVectorIdxConstant(0, DL));
+    Parts[0] = Val;
+    return true;
+  }
+
   if (ValueVT.isScalableVector() && PartVT.isScalableVector()) {
     LLVMContext &Context = *DAG.getContext();
     EVT ValueEltVT = ValueVT.getVectorElementType();
@@ -21344,22 +21364,6 @@ bool RISCVTargetLowering::splitValueIntoRegisterParts(
     }
   }
 
-  if (ValueVT.isRISCVVectorTuple() && PartVT.isRISCVVectorTuple()) {
-    unsigned ValNF = ValueVT.getRISCVVectorTupleNumFields();
-    [[maybe_unused]] unsigned ValLMUL =
-        divideCeil(ValueVT.getSizeInBits(), ValNF * RISCV::RVVBitsPerBlock);
-    unsigned PartNF = PartVT.getRISCVVectorTupleNumFields();
-    [[maybe_unused]] unsigned PartLMUL =
-        divideCeil(PartVT.getSizeInBits(), PartNF * RISCV::RVVBitsPerBlock);
-    assert(ValNF == PartNF && ValLMUL == PartLMUL &&
-           "RISC-V vector tuple type only accepts same register class type "
-           "TUPLE_INSERT");
-
-    Val = DAG.getNode(RISCVISD::TUPLE_INSERT, DL, PartVT, DAG.getUNDEF(PartVT),
-                      Val, DAG.getVectorIdxConstant(0, DL));
-    Parts[0] = Val;
-    return true;
-  }
   return false;
 }
 
@@ -21378,6 +21382,9 @@ SDValue RISCVTargetLowering::joinRegisterPartsIntoValue(
     return Val;
   }
 
+  if (ValueVT.isRISCVVectorTuple())
+    return SDValue();
+
   if (ValueVT.isScalableVector() && PartVT.isScalableVector()) {
     LLVMContext &Context = *DAG.getContext();
     SDValue Val = Parts[0];

``````````

</details>


https://github.com/llvm/llvm-project/pull/114329