[RISCV] Use RVVBitsPerBlock in assignRVVStackObjectOffsets and adjustReg. NFC (#109848)

I think the 8 here represents RVVBitsPerBlock / 8.

Author: topperc

llvm/lib/Target/RISCV/RISCVFrameLowering.cpp

@@ -1090,11 +1090,12 @@ RISCVFrameLowering::assignRVVStackObjectOffsets(MachineFunction &MF) const {
   for (int FI : ObjectsToAllocate) {
     // ObjectSize in bytes.
     int64_t ObjectSize = MFI.getObjectSize(FI);
-    auto ObjectAlign = std::max(Align(8), MFI.getObjectAlign(FI));
+    auto ObjectAlign =
+        std::max(Align(RISCV::RVVBitsPerBlock / 8), MFI.getObjectAlign(FI));
     // If the data type is the fractional vector type, reserve one vector
     // register for it.
-    if (ObjectSize < 8)
-      ObjectSize = 8;
+    if (ObjectSize < (RISCV::RVVBitsPerBlock / 8))
+      ObjectSize = (RISCV::RVVBitsPerBlock / 8);
     Offset = alignTo(Offset + ObjectSize, ObjectAlign);
     MFI.setObjectOffset(FI, -Offset);
     // Update the maximum alignment of the RVV stack section

llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp

@@ -200,11 +200,11 @@ void RISCVRegisterInfo::adjustReg(MachineBasicBlock &MBB,
       ScratchReg = MRI.createVirtualRegister(&RISCV::GPRRegClass);
 
     assert(ScalableValue > 0 && "There is no need to get VLEN scaled value.");
-    assert(ScalableValue % 8 == 0 &&
+    assert(ScalableValue % (RISCV::RVVBitsPerBlock / 8) == 0 &&
            "Reserve the stack by the multiple of one vector size.");
-    assert(isInt<32>(ScalableValue / 8) &&
+    assert(isInt<32>(ScalableValue / (RISCV::RVVBitsPerBlock / 8)) &&
            "Expect the number of vector registers within 32-bits.");
-    uint32_t NumOfVReg = ScalableValue / 8;
+    uint32_t NumOfVReg = ScalableValue / (RISCV::RVVBitsPerBlock / 8);
     BuildMI(MBB, II, DL, TII->get(RISCV::PseudoReadVLENB), ScratchReg)
         .setMIFlag(Flag);