llvm-project

Commit Graph

Author	SHA1	Message	Date
Simon Pilgrim	775bf62698	[SystemZ] Regenerate rotate/shift tests	2020-03-15 16:42:46 +00:00
Jonas Paulsson	f76fe45426	[SystemZ] Improve instruction selection of 64 bit shifts and rotates. For shift and rotate instructions that only use the last 6 bits of the shift amount, a shift amount of (x*64-s) can be substituted with (-s). This saves one instruction and a register: lhi %r1, 64 sr %r1, %r3 sllg %r2, %r2, 0(%r1) => lcr %r1, %r3 sllg %r2, %r2, 0(%r1) Review: Ulrich Weigand llvm-svn: 357481	2019-04-02 15:36:30 +00:00

Author

SHA1

Message

Date

Simon Pilgrim

775bf62698

[SystemZ] Regenerate rotate/shift tests

2020-03-15 16:42:46 +00:00

Jonas Paulsson

f76fe45426

[SystemZ] Improve instruction selection of 64 bit shifts and rotates.

For shift and rotate instructions that only use the last 6 bits of the shift
amount, a shift amount of (x*64-s) can be substituted with (-s). This saves
one instruction and a register:

  lhi     %r1, 64
  sr      %r1, %r3
  sllg    %r2, %r2, 0(%r1)
  =>
  lcr     %r1, %r3
  sllg    %r2, %r2, 0(%r1)

Review: Ulrich Weigand
llvm-svn: 357481

2019-04-02 15:36:30 +00:00

2 Commits