118d4234ac
On 64-bit target, prefer using RDPC over CALL to get the value of %pc. This is faster on modern processors (Niagara T1 and newer) and avoids polluting the processor's predictor state. The old behavior of using a fake CALL is still done when tuning for classic UltraSPARC processors, since RDPC is much slower there. A quick pgbench test on a SPARC T4 shows about 2% speedup on SELECT loads, and about 7% speedup on INSERT/UPDATE loads. Reviewed By: @s-barannikov Github PR: https://github.com/llvm/llvm-project/pull/78280