Extend pre-emit peephole for S_CBRANCH_VCC[N]Z to eliminate
redundant S_AND operations against EXEC for V_CMP results in VCC.
These occur after after register allocation when VCC has been
selected as the comparison destination.
Reviewed By: rampitec
Differential Revision: https://reviews.llvm.org/D120202
Introduce V_MOV_B32_indirect_read for indexed vgpr reads
(and rename the old V_MOV_B32_indirect to
V_MOV_B32_indirect_write) so they can be unambiguously
distinguished from regular V_MOV_B32_e32. Previously they
were distinguished by looking for extra implicit operands
but this is fragile because regular moves sometimes have
extra implicit operands too:
- either by accident, when instructions end up with
duplicate implicit operands (see e.g. D100939)
- or by design, when SIInstrInfo::copyPhysReg breaks a
multi-dword copy into individual subreg mov instructions
and adds implicit operands for the super-register.
The effect of this is that SIInstrInfo::isFoldableCopy can
be simplified and identifies more foldable copies. The test
diffs show that more immediate 0 values have been folded as
inline operands.
SIInstrInfo::isReallyTriviallyReMaterializable could
probably be simplified too but that is not part of this
patch.
Differential Revision: https://reviews.llvm.org/D114230
SIPreEmitPeephole did not try to remove redundant s_set_gpr_idx_*
instructions in blocks that end with a conditional branch instruction.
This seems like a simple oversight.
Differential Revision: https://reviews.llvm.org/D101629
Pass no longer handles skips. Pass now removes unnecessary
unconditional branches and lowers early termination branches.
Hence rename to SILateBranchLowering.
Move code to handle returns to epilog from SIPreEmitPeephole
into SILateBranchLowering. This means SIPreEmitPeephole only
contains optional optimisations, and all required transforms
are in SILateBranchLowering.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D98915
SIRemoveShortExecBranches is an optimisation so fits well in the
context of SIPreEmitPeephole.
Test changes relate to early termination from kills which have now
been lowered prior to considering branches for removal.
As these use s_cbranch the execz skips are now retained instead.
Currently either behaviour is valid as kill with EXEC=0 is a nop;
however, if early termination is used differently in future then
the new behaviour is the correct one.
Reviewed By: foad
Differential Revision: https://reviews.llvm.org/D98917
Add code so duplication index register changes can be removed from
inside bundles.
Reviewed By: rampitec, foad
Differential Revision: https://reviews.llvm.org/D98940
SIPreEmitPeephole does not process all terminators, which means
it can fail to handle SI_RETURN_TO_EPILOG if immediately preceeded
by a branch to the early exit block.
Reviewed By: rampitec
Differential Revision: https://reviews.llvm.org/D85872
When SCC is dead, but VCC is required then replace s_and / s_andn2
with s_mov into VCC when mask value is 0 or -1.
Reviewed By: rampitec
Differential Revision: https://reviews.llvm.org/D83850
Add handling of s_andn2 and mask of 0.
This eliminates redundant instructions from uniform control flow.
Reviewed By: rampitec
Differential Revision: https://reviews.llvm.org/D83641
For now, moving it to SIPreEmitPeephole.
Should find a right place to have this code.
Reviewed By: nhaehnle
Differential revision: https://reviews.llvm.org/D77544
This pass can handle all the optimization
opportunities found just before code emission.
Presently it includes the handling of vcc branch
optimization that was handled earlier in SIInsertSkips.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D76712
