[llvm] [RISCV][MC] Prioritize features in MultiMismatchFallback (PR #215737)

[Alexander Richardson via llvm-commits]

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@@ -7,13 +7,23 @@ flh ft1, -2049(a0) # CHECK: :[[@LINE]]:10: error: operand must be a symbol with
 fsh ft2, 2048(a1) # CHECK: :[[@LINE]]:10: error: operand must be a symbol with %lo/%pcrel_lo/%tprel_lo specifier or an integer in the range [-2048, 2047]
 
 # Integer registers where FP regs are expected
-fcvt.l.h ft0, a0 # CHECK: :[[@LINE]]:10: error: register must be a GPR
-fcvt.lu.h ft1, a1 # CHECK: :[[@LINE]]:11: error: register must be a GPR
+fcvt.l.h ft0, a0 
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arichardson wrote:

I found that these error-checking tests are rather fragile since extra diagnostics don't fail the tests. I have a series of draft changes that add `llvm-mc -verify=<prefixes` support in the same way that clang does. So you can then add `// expected-error {{message}}` etc. and get an error if there is an unexpected diagnostic.

https://github.com/llvm/llvm-project/pull/215737