[llvm] [GISEL] Fix bugs in G_EXTRACT_SUBVECTOR definition (PR #108848)

[Craig Topper via llvm-commits]

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@@ -1788,7 +1788,7 @@ void MachineVerifier::verifyPreISelGenericInstruction(const MachineInstr *MI) {
     }
 
     uint64_t SrcMinLen = SrcTy.getElementCount().getKnownMinValue();
-    if (SrcTy.isScalable() && DstTy.isScalable() &&
+    if (SrcTy.isScalable() == DstTy.isScalable() &&
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topperc wrote:

Well I was thinking you need to either disallow the mixed case or check that we don't have the unsupported mixed case of scalable dest and fixed source. So some check needs to exist.

https://github.com/llvm/llvm-project/pull/108848