llvm-project

Commit Graph

Author	SHA1	Message	Date
Simon Pilgrim	68224c1952	[TargetLowering] Only demand a rotation's modulo amount bits ISD::ROTL/ROTR rotation values are guaranteed to act as a modulo amount, so for power-of-2 bitwidths we only need the lowest bits. Differential Revision: https://reviews.llvm.org/D76201	2020-03-17 21:23:46 +00:00
Simon Pilgrim	775bf62698	[SystemZ] Regenerate rotate/shift tests	2020-03-15 16:42:46 +00:00
Elliot Colp	bc2cfc2291	[SystemZ] Remove AND mask of bottom 6 bits when result is used for shift/rotate On SystemZ, shift and rotate instructions only use the bottom 6 bits of the shift/rotate amount. Therefore, if the amount is ANDed with an immediate mask that has all of the bottom 6 bits set, we can remove the AND operation entirely. Differential Revision: http://reviews.llvm.org/D21854 llvm-svn: 274650	2016-07-06 18:13:11 +00:00

Author

SHA1

Message

Date

Simon Pilgrim

68224c1952

[TargetLowering] Only demand a rotation's modulo amount bits

ISD::ROTL/ROTR rotation values are guaranteed to act as a modulo amount, so for power-of-2 bitwidths we only need the lowest bits.

Differential Revision: https://reviews.llvm.org/D76201

2020-03-17 21:23:46 +00:00

Simon Pilgrim

775bf62698

[SystemZ] Regenerate rotate/shift tests

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

Elliot Colp

bc2cfc2291

[SystemZ] Remove AND mask of bottom 6 bits when result is used for shift/rotate

On SystemZ, shift and rotate instructions only use the bottom 6 bits of the shift/rotate amount.
Therefore, if the amount is ANDed with an immediate mask that has all of the bottom 6 bits set, we
can remove the AND operation entirely.

Differential Revision: http://reviews.llvm.org/D21854

llvm-svn: 274650

2016-07-06 18:13:11 +00:00

3 Commits