[llvm-branch-commits] [llvm] [RISCV][MC] Warn if SEW/LMUL may not be compatible (PR #94313)

[Luke Lau via llvm-branch-commits]

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@@ -2211,6 +2222,16 @@ ParseStatus RISCVAsmParser::parseVTypeI(OperandVector &Operands) {
 
   if (getLexer().is(AsmToken::EndOfStatement) && State == VTypeState_Done) {
     RISCVII::VLMUL VLMUL = RISCVVType::encodeLMUL(Lmul, Fractional);
+    if (Fractional) {
+      unsigned ELEN = STI->hasFeature(RISCV::FeatureStdExtZve64x) ? 64 : 32;
+      unsigned MaxSEW = ELEN / Lmul;
+      // If MaxSEW < 8, we should have printed warning about reserved LMUL.
+      if (MaxSEW >= 8 && Sew > MaxSEW)
+        Warning(SEWLoc,
+                "use of vtype encodings with SEW > " + Twine(MaxSEW) +
+                    " and LMUL == " + (Fractional ? "mf" : "m") + Twine(Lmul) +
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lukel97 wrote:

Fractional is always true here right?

https://github.com/llvm/llvm-project/pull/94313