[llvm] [LoopVectorizer] Only check register pressure for VFs that have been enabled via maxBandwidth (PR #149056)

[Sam Tebbs via llvm-commits]

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@@ -85,8 +85,11 @@ struct VPRegisterUsage {
   SmallMapVector<unsigned, unsigned, 4> MaxLocalUsers;
 
   /// Check if any of the tracked live intervals exceeds the number of
-  /// available registers for the target.
-  bool exceedsMaxNumRegs(const TargetTransformInfo &TTI) const;
+  /// available registers for the target. Specifying OverrideMaxNumRegs
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SamTebbs33 wrote:

I think the added comment could be better worded as "If non-zero, OverrideMaxNumRegs will be used in place of the target's number of registers.".

https://github.com/llvm/llvm-project/pull/149056