diff options
| author | Stefan Pintilie <stefanp@ca.ibm.com> | 2019-05-24 12:05:37 +0000 |
|---|---|---|
| committer | Stefan Pintilie <stefanp@ca.ibm.com> | 2019-05-24 12:05:37 +0000 |
| commit | 522307fa40da4b4d892e273c058418e112d844a4 (patch) | |
| tree | 3779970bb54487bc7086916edbabea054548c22e /llvm/lib/Target/PowerPC | |
| parent | 33bee053c39b46c6aa46abca6cc758979da44b14 (diff) | |
| download | bcm5719-llvm-522307fa40da4b4d892e273c058418e112d844a4.tar.gz bcm5719-llvm-522307fa40da4b4d892e273c058418e112d844a4.zip | |
[PowerPC] Remove CRBits Copy Of Unset/set CBit
For the situation, where we generate the following code:
crxor 8, 8, 8
< Some instructions>
.LBB0_1:
< Some instructions>
cror 1, 8, 8
cror (COPY of CRbit) depends on the result of the crxor instruction.
CR8 is known to be zero as crxor is equivalent to CRUNSET. We can simply use
crxor 1, 1, 1 instead to zero out CR1, which does not have any dependency on
any previous instruction.
This patch will optimize it to:
< Some instructions>
.LBB0_1:
< Some instructions>
cror 1, 1, 1
Patch By: Victor Huang (NeHuang)
Differential Revision: https://reviews.llvm.org/D62044
llvm-svn: 361632
Diffstat (limited to 'llvm/lib/Target/PowerPC')
| -rw-r--r-- | llvm/lib/Target/PowerPC/PPCInstrInfo.cpp | 2 | ||||
| -rw-r--r-- | llvm/lib/Target/PowerPC/PPCInstrInfo.td | 2 |
2 files changed, 4 insertions, 0 deletions
diff --git a/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp b/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp index a03742d7402..25f4c9aa8eb 100644 --- a/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp +++ b/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp @@ -341,6 +341,8 @@ bool PPCInstrInfo::isReallyTriviallyReMaterializable(const MachineInstr &MI, case PPC::V_SETALLONESB: case PPC::V_SETALLONESH: case PPC::V_SETALLONES: + case PPC::CRSET: + case PPC::CRUNSET: return true; } return false; diff --git a/llvm/lib/Target/PowerPC/PPCInstrInfo.td b/llvm/lib/Target/PowerPC/PPCInstrInfo.td index 64511a0c79e..14fe0cd87fa 100644 --- a/llvm/lib/Target/PowerPC/PPCInstrInfo.td +++ b/llvm/lib/Target/PowerPC/PPCInstrInfo.td @@ -2546,6 +2546,7 @@ def CRORC : XLForm_1<19, 417, (outs crbitrc:$CRD), [(set i1:$CRD, (or i1:$CRA, (not i1:$CRB)))]>; let isCodeGenOnly = 1 in { +let isReMaterializable = 1, isAsCheapAsAMove = 1 in { def CRSET : XLForm_1_ext<19, 289, (outs crbitrc:$dst), (ins), "creqv $dst, $dst, $dst", IIC_BrCR, [(set i1:$dst, 1)]>; @@ -2553,6 +2554,7 @@ def CRSET : XLForm_1_ext<19, 289, (outs crbitrc:$dst), (ins), def CRUNSET: XLForm_1_ext<19, 193, (outs crbitrc:$dst), (ins), "crxor $dst, $dst, $dst", IIC_BrCR, [(set i1:$dst, 0)]>; +} let Defs = [CR1EQ], CRD = 6 in { def CR6SET : XLForm_1_ext<19, 289, (outs), (ins), |
