[llvm] [RISCV] Report all near-miss reasons in the AsmParser (PR #205721)

[Mark Zhuang via llvm-commits]

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@@ -8,10 +8,10 @@ cv.extract t0, t1, 0
 # CHECK-ERROR: too few operands for instruction
 
 cv.extract t0, t1, t2
-# CHECK-ERROR: immediate must be an integer in the range [0, 31]
+# CHECK-ERROR: invalid instruction
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zqb-all wrote:

This looks like a multiple-mismatch issue. t2 fails UImm5 at operand 3 (recording the "immediate must be in [0, 31]" near-miss), then operand 4 is missing — two problems, so the candidate is dropped and leaving the bare invalid instruction.

Keeping the first near-miss instead of discarding it on the second mismatch seemed to recover most of these. It'd be in AsmMatcherEmitter so it affects ARM too — does that direction seem reasonable to you?

https://github.com/llvm/llvm-project/pull/205721