[llvm] [RISCV] Set the isMoveReg flag for FMV_X_W (PR #109378)

[Craig Topper via llvm-commits]

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@@ -388,11 +388,11 @@ foreach Ext = FExts in {
 } // foreach Ext = FExts
 
 let Predicates = [HasStdExtF], mayRaiseFPException = 0,
-    IsSignExtendingOpW = 1 in
+    IsSignExtendingOpW = 1, isMoveReg = 1 in
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topperc wrote:

I'm not sure what all isMoveReg is used for. On RV64, this instruction has sign extending behavior. It might not be safe to do generic optimizations with it.

https://github.com/llvm/llvm-project/pull/109378