Previously, 34-bit constants were materialized in selectI64Imm(), and we relied
on td pattern matching to instead produce a pli. This becomes problematic as
there is no guarantee that the 34-bit constant will reach the td pattern
selection for pli. It is also possible for other transformations (such as complex
bit permutations) to also produce and utilize the 34-bit constant materialized
through selectI64Imm().
This patch instead produces pli on Power10 directly whenever the constant fits
within 34-bits.
Differential Revision: https://reviews.llvm.org/D99906
Starting with Power 10 the instruction paddi is available to use.
The instruction allows for immediates that are 34 bits.
This patch adds exploitation of the paddi instruction to allow us
to materialize constants.
Reviewed By: lei, amyk
Differential Revision: https://reviews.llvm.org/D93300
NOTE: This patch was originally written by Anil Mahmud. His code has been
rebased but otherwise left mostly unchanged.
A new instructon on Power 10 allows for the materialization of 34 bit
immediate values. This patch allows the compiler to take advantage of
the new instruction in this situation.
Reviewed By: amyk
Differential Revision: https://reviews.llvm.org/D92879
Amy Kwan