This patch removes the following dag node opcodes from namespace X86ISD:
RDTSC_DAG, RDTSCP_DAG, RDPMC_DAG
The logic that expands RDTSC/RDPMC/XGETBV intrinsics is basically the same. The only differences are:
- RDTSC/RDTSCP don't implicitly read ECX.
- RDTSCP also implicitly writes ECX.
I moved the common expansion logic into a helper function with the goal to get rid of code repetition.
That helper is now used for the expansion of RDTSC/RDTSCP/RDPMC/XGETBV intrinsics.
No functional change intended.