Without this, MachineCSE is powerless to handle redundant operations with truncated source operands.
This required fixing the 2-addr pass to handle tied subregisters. It isn't clear what combinations of subregisters can legally be tied, but the simple case of truncated source operands is now safely handled:
%vreg11<def> = COPY %vreg1:sub_32bit; GR32:%vreg11 GR64:%vreg1
%vreg12<def> = COPY %vreg2:sub_32bit; GR32:%vreg12 GR64:%vreg2
%vreg13<def,tied1> = ADD32rr %vreg11<tied0>, %vreg12<kill>, %EFLAGS<imp-def>
Test case: cse-add-with-overflow.ll.
This exposed an existing bug in
PPCInstrInfo::commuteInstruction. Thanks to Rafael for the test case:
PowerPC/crash.ll.
llvm-svn: 197465
that it coalesces normal copies.
Without this, MachineCSE is powerless to handle redundant operations
with truncated source operands.
This required fixing the 2-addr pass to handle tied subregisters. It
isn't clear what combinations of subregisters can legally be tied, but
the simple case of truncated source operands is now safely handled:
%vreg11<def> = COPY %vreg1:sub_32bit; GR32:%vreg11 GR64:%vreg1
%vreg12<def> = COPY %vreg2:sub_32bit; GR32:%vreg12 GR64:%vreg2
%vreg13<def,tied1> = ADD32rr %vreg11<tied0>, %vreg12<kill>, %EFLAGS<imp-def>
llvm-svn: 197414
The Segment struct contains a single interval; multiple instances of this struct
are used to construct a live range, but the struct is not a live range by
itself.
llvm-svn: 192392
at all of the operands. Previously it was skipping over implicit operands which
cause infinite looping when the two-address pass try to reschedule a
two-address instruction below the kill of tied operand.
I'm unable to come up with a reasonably sized test case.
rdar://13747577
llvm-svn: 180906
When MachineScheduler is enabled, this functionality can be
removed. Until then, provide a way to disable it for test cases and
designing MachineScheduler heuristics.
llvm-svn: 180192
itself recursively with a new instruction that has not been finalized, in order
to determine whether to keep the instruction. On 'make check' and test-suite the
only cases where the recursive invocation made any transformations were simple
instruction commutations, so I am restricting the recursive invocation to do
only this.
The other cases wouldn't work correctly when updating LiveIntervals, since the
new instructions don't have slot indices and LiveIntervals hasn't yet been
updated. If the other transformations were actually triggering in any test case
it would be possible to support it with a lot of effort, but since they don't
it's not worth it.
llvm-svn: 175979
unless it was requested to with an optional parameter that defaults to false, so
we don't need to handle that case in TwoAddressInstructionPass.
llvm-svn: 175974
TwoAddressInstructionPass. The code in rescheduleMIBelowKill() is a bit tricky,
since multiple instructions need to be moved down, one-at-a-time, in reverse
order.
llvm-svn: 175955
pass. One of the callers of isKilled() can cope with overapproximation of kills
and the other can't, so I added a flag to indicate this.
In theory this could pessimize code slightly, but in practice most physical
register uses are kills, and most important kills of physical registers are the
only uses of that register prior to register allocation, so we can recognize
them as kills even without kill flags.
This is relevant because LiveIntervals gets rid of all kill flags.
llvm-svn: 175821
available.
With this commit there are no longer any assertion or verifier failures when
running 'make check' without LiveVariables. There are still 56 failing tests
with codegen differences and 1 unexpectedly passing test.
llvm-svn: 175719
Andrew Trick
Rafael Espindola
Matthias Braun
Craig Topper
Evan Cheng
Bill Wendling
Cameron Zwarich
David Blaikie