Summary: As Bugzilla-35090 reported, the rationale for using custom lowering SREM/UREM should no longer be true. At the IR level, the div-rem-pairs pass performs the transformation where the remainder is computed from the result of the division when both a required. We should now be able to lower these directly on P9. And the pass also fixed the problem that divide is in a different block than the remainder. This is a patch to remove redundant code and make SREM/UREM legal directly on P9.
Reviewed By: lkail
Differential Revision: https://reviews.llvm.org/D82145
This patch introduces a TargetLowering query, isMulhCheaperThanMulShift.
Currently in DAG Combine, it will transform mulhs/mulhu into a
wider multiply and a shift if the wide multiply is legal.
This TLI function is implemented on 64-bit PowerPC, as it is more desirable to
have multiply-high over multiply + shift for words and doublewords. Having
multiply-high can also aid in further transformations that can be done.
Differential Revision: https://reviews.llvm.org/D78271
Note that if we need the result of both the divide and the modulo then we
compute the modulo based on the result of the divide and not using the new
hardware instruction.
Commit on behalf of STEFAN PINTILIE.
Differential Revision: https://reviews.llvm.org/D33940
llvm-svn: 305210
