| commit | 824e9f2e51a5f5536577bc7aa595d3262b442300 | |
| author | segher <segher@138bc75d-0d04-0410-961f-82ee72b054a4> | |
| Fri, 9 Dec 2016 19:31:06 +0000 (9 19:31 +0000) | ||
| committer | segher <segher@138bc75d-0d04-0410-961f-82ee72b054a4> | |
| Fri, 9 Dec 2016 19:31:06 +0000 (9 19:31 +0000) | ||
| tree | 025154146b8b80c430204be6d22a894a97eea00f | treesnapshot (tar.gz zip) |
| parent | b317b227cbb1f2bec8c2b1421bd0e6d6d467d1d1 | commitdiff |
rs6000: clz/ctz/ffs improvement (PR78683)
On CPUs that implement popcnt[wd] but not cnttz[wd] we can do better for
the ctz sequences than we do today.
CL[TZ]_DEFINED_VALUE_AT_ZERO can return 2, since we always return the
same fixed value (only dependent on TARGET_* options).
PR target/78683
* config/rs6000/rs6000.h (CLZ_DEFINED_VALUE_AT_ZERO): Use
GET_MODE_BITSIZE. Return 2.
(CTZ_DEFINED_VALUE_AT_ZERO): Use GET_MODE_BITSIZE. Return 2. Handle
TARGET_POPCNTD the same as TARGET_CTZ.
* config/rs6000/rs6000.md (ctz<mode>2): Reimplement.
(ffs<mode>2): Reimplement.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@243499 138bc75d-0d04-0410-961f-82ee72b054a4
On CPUs that implement popcnt[wd] but not cnttz[wd] we can do better for
the ctz sequences than we do today.
CL[TZ]_DEFINED_VALUE_AT_ZERO can return 2, since we always return the
same fixed value (only dependent on TARGET_* options).
PR target/78683
* config/rs6000/rs6000.h (CLZ_DEFINED_VALUE_AT_ZERO): Use
GET_MODE_BITSIZE. Return 2.
(CTZ_DEFINED_VALUE_AT_ZERO): Use GET_MODE_BITSIZE. Return 2. Handle
TARGET_POPCNTD the same as TARGET_CTZ.
* config/rs6000/rs6000.md (ctz<mode>2): Reimplement.
(ffs<mode>2): Reimplement.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@243499 138bc75d-0d04-0410-961f-82ee72b054a4
| gcc/ChangeLog | diffblobblamehistory | |
| gcc/config/rs6000/rs6000.h | diffblobblamehistory | |
| gcc/config/rs6000/rs6000.md | diffblobblamehistory |