[InstCombine] Slightly optimize visitFcmp (NFC) (#156097)

Studying the code related to float found a slightly optimal sequence of
actions.

Author: Seraphimt

llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp

@@ -8944,14 +8944,14 @@ Instruction *InstCombinerImpl::visitFCmpInst(FCmpInst &I) {
   }
 
   {
-    Value *CanonLHS = nullptr, *CanonRHS = nullptr;
+    Value *CanonLHS = nullptr;
     match(Op0, m_Intrinsic<Intrinsic::canonicalize>(m_Value(CanonLHS)));
-    match(Op1, m_Intrinsic<Intrinsic::canonicalize>(m_Value(CanonRHS)));
-
     // (canonicalize(x) == x) => (x == x)
     if (CanonLHS == Op1)
       return new FCmpInst(Pred, Op1, Op1, "", &I);
 
+    Value *CanonRHS = nullptr;
+    match(Op1, m_Intrinsic<Intrinsic::canonicalize>(m_Value(CanonRHS)));
     // (x == canonicalize(x)) => (x == x)
     if (CanonRHS == Op0)
       return new FCmpInst(Pred, Op0, Op0, "", &I);