[llvm] [LV][NFC] Use APFloat class when printing out costs per lane (PR #201824)

[David Sherwood via llvm-commits]

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@@ -266,3 +272,5 @@ exit:
   store i64 %acc3.exit, ptr %arrayidx45, align 8
   ret void
 }
+;; NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
+; CHECK: {{.*}}
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david-arm wrote:

Sadly not. This is exactly what update_analyze_test_checks.py generates each time. I think it's because there are no common CHECK lines. I can fix this by changing the RUN lines from `--check-prefixes=CHECK,CHECK-NOPRESSURE` to `--check-prefixes=CHECK-NOPRESSURE`, etc.

https://github.com/llvm/llvm-project/pull/201824