[llvm] [AMDGPU][True16] added Pre-RA hint to improve copy elimination (PR #103366)

[Jay Foad via llvm-commits]

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@@ -22,12 +22,22 @@
 /// although the same shall be possible with other register classes and
 /// instructions if necessary.
 ///
+/// This pass also adds register allocation hints to COPY.
+/// The hints will be post-processed by SIRegisterInfo::getRegAllocationHints.
+/// When using True16, we often see COPY moving a 16-bit value between a VGPR_32
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jayfoad wrote:

These three lines are duplicated below.

https://github.com/llvm/llvm-project/pull/103366