[llvm] [GISEL] More accounting for scalable vectors when operating on LLTs (PR #80372)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-globalisel

Author: Michael Maitland (michaelmaitland)

<details>
<summary>Changes</summary>

This will be stacked on by a PR I am currently working on.

---
Full diff: https://github.com/llvm/llvm-project/pull/80372.diff


2 Files Affected:

- (modified) llvm/lib/CodeGen/GlobalISel/CallLowering.cpp (+7-6) 
- (modified) llvm/lib/CodeGen/MachineVerifier.cpp (+4-3) 


``````````diff
diff --git a/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp b/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
index ccd9b13d730b6..3bd1542eeb746 100644
--- a/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
@@ -412,7 +412,7 @@ static void buildCopyFromRegs(MachineIRBuilder &B, ArrayRef<Register> OrigRegs,
     // size, e.g. PartLLT == v2s64 and LLTy is v3s32, then first coerce it to
     // have the same elt type, i.e. v4s32.
     // TODO: Extend this coersion to element multiples other than just 2.
-    if (PartLLT.getSizeInBits() > LLTy.getSizeInBits() &&
+    if (TypeSize::isKnownGT(PartLLT.getSizeInBits(), LLTy.getSizeInBits()) &&
         PartLLT.getScalarSizeInBits() == LLTy.getScalarSizeInBits() * 2 &&
         Regs.size() == 1) {
       LLT NewTy = PartLLT.changeElementType(LLTy.getElementType())
@@ -529,7 +529,7 @@ static void buildCopyToRegs(MachineIRBuilder &B, ArrayRef<Register> DstRegs,
   // We could just insert a regular copy, but this is unreachable at the moment.
   assert(SrcTy != PartTy && "identical part types shouldn't reach here");
 
-  const unsigned PartSize = PartTy.getSizeInBits();
+  const TypeSize PartSize = PartTy.getSizeInBits();
 
   if (PartTy.isVector() == SrcTy.isVector() &&
       PartTy.getScalarSizeInBits() > SrcTy.getScalarSizeInBits()) {
@@ -539,7 +539,7 @@ static void buildCopyToRegs(MachineIRBuilder &B, ArrayRef<Register> DstRegs,
   }
 
   if (SrcTy.isVector() && !PartTy.isVector() &&
-      PartSize > SrcTy.getElementType().getSizeInBits()) {
+      TypeSize::isKnownGT(PartSize, SrcTy.getElementType().getSizeInBits())) {
     // Vector was scalarized, and the elements extended.
     auto UnmergeToEltTy = B.buildUnmerge(SrcTy.getElementType(), SrcReg);
     for (int i = 0, e = DstRegs.size(); i != e; ++i)
@@ -548,9 +548,10 @@ static void buildCopyToRegs(MachineIRBuilder &B, ArrayRef<Register> DstRegs,
   }
 
   if (SrcTy.isVector() && PartTy.isVector() &&
-      PartTy.getScalarSizeInBits() == SrcTy.getScalarSizeInBits() &&
-      SrcTy.getNumElements() < PartTy.getNumElements()) {
-    // A coercion like: v2f32 -> v4f32.
+      PartTy.getSizeInBits() == SrcTy.getSizeInBits() &&
+      ElementCount::isKnownLT(SrcTy.getElementCount(),
+                              PartTy.getElementCount())) {
+    // A coercion like: v2f32 -> v4f32 or nxv2f32 -> nxv4f32
     Register DstReg = DstRegs.front();
     B.buildPadVectorWithUndefElements(DstReg, SrcReg);
     return;
diff --git a/llvm/lib/CodeGen/MachineVerifier.cpp b/llvm/lib/CodeGen/MachineVerifier.cpp
index b182000a3d705..fe865ed6f8a0e 100644
--- a/llvm/lib/CodeGen/MachineVerifier.cpp
+++ b/llvm/lib/CodeGen/MachineVerifier.cpp
@@ -1400,7 +1400,8 @@ void MachineVerifier::verifyPreISelGenericInstruction(const MachineInstr *MI) {
     if (DstTy.isVector()) {
       // This case is the converse of G_CONCAT_VECTORS.
       if (!SrcTy.isVector() || SrcTy.getScalarType() != DstTy.getScalarType() ||
-          SrcTy.getNumElements() != NumDsts * DstTy.getNumElements())
+          SrcTy.isScalableVector() != DstTy.isScalableVector() ||
+          SrcTy.getSizeInBits() != NumDsts * DstTy.getSizeInBits())
         report("G_UNMERGE_VALUES source operand does not match vector "
                "destination operands",
                MI);
@@ -1477,8 +1478,8 @@ void MachineVerifier::verifyPreISelGenericInstruction(const MachineInstr *MI) {
     for (const MachineOperand &MO : llvm::drop_begin(MI->operands(), 2))
       if (MRI->getType(MI->getOperand(1).getReg()) != MRI->getType(MO.getReg()))
         report("G_CONCAT_VECTOR source operand types are not homogeneous", MI);
-    if (DstTy.getNumElements() !=
-        SrcTy.getNumElements() * (MI->getNumOperands() - 1))
+    if (DstTy.getElementCount() !=
+        SrcTy.getElementCount() * (MI->getNumOperands() - 1))
       report("G_CONCAT_VECTOR num dest and source elements should match", MI);
     break;
   }

``````````

</details>


https://github.com/llvm/llvm-project/pull/80372