LiveVariableAnalysis was a bit picky about a register only being redefined once,
but that really isn't necessary.
Here is an example of chained INSERT_SUBREGs that we can handle now:
68 %reg1040<def> = INSERT_SUBREG %reg1040, %reg1028<kill>, 14
register: %reg1040 +[70,134:0)
76 %reg1040<def> = INSERT_SUBREG %reg1040, %reg1029<kill>, 13
register: %reg1040 replace range with [70,78:1) RESULT: %reg1040,0.000000e+00 = [70,78:1)[78,134:0) 0@78-(134) 1@70-(78)
84 %reg1040<def> = INSERT_SUBREG %reg1040, %reg1030<kill>, 12
register: %reg1040 replace range with [78,86:2) RESULT: %reg1040,0.000000e+00 = [70,78:1)[78,86:2)[86,134:0) 0@86-(134) 1@70-(78) 2@78-(86)
92 %reg1040<def> = INSERT_SUBREG %reg1040, %reg1031<kill>, 11
register: %reg1040 replace range with [86,94:3) RESULT: %reg1040,0.000000e+00 = [70,78:1)[78,86:2)[86,94:3)[94,134:0) 0@94-(134) 1@70-(78) 2@78-(86) 3@86-(94)
rdar://problem/8096390
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106152 91177308-0d34-0410-b5e6-96231b3b80d8
will conflict with another live range. The place which creates this scenerio is
the code in X86 that lowers a select instruction by splitting the MBBs. This
eliminates the need to check from the bottom up in an MBB for live pregs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106066 91177308-0d34-0410-b5e6-96231b3b80d8
SimpleRegisterCoalescing::JoinIntervals() uses CoalescerPair to determine if a
copy is coalescable, and in very rare cases it can return true where LHS is not
live - the coalescable copy can come from an alias of the physreg in LHS.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106021 91177308-0d34-0410-b5e6-96231b3b80d8
combined to an insert_subreg, i.e., where the destination register is larger
than the source. We need to check that the subregs can be composed for that
case in a symmetrical way to the case when the destination is smaller.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106004 91177308-0d34-0410-b5e6-96231b3b80d8
Early clobbers defining a virtual register were first alocated to a physreg and
then processed as a physreg EC, spilling the virtreg.
This fixes PR7382.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105998 91177308-0d34-0410-b5e6-96231b3b80d8
Given a copy instruction, CoalescerPair can determine which registers to
coalesce in order to eliminate the copy. It deals with all the subreg fun to
determine a tuple (DstReg, SrcReg, SubIdx) such that:
- SrcReg is a virtual register that will disappear after coalescing.
- DstReg is a virtual or physical register whose live range will be extended.
- SubIdx is 0 when DstReg is a physical register.
- SrcReg can be joined with DstReg:SubIdx.
CoalescerPair::isCoalescable() determines if another copy instruction is
compatible with the same tuple. This fixes some NEON miscompilations where
shuffles are getting coalesced as if they were copies.
The CoalescerPair class will replace a lot of the spaghetti logic in JoinCopy
later.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105997 91177308-0d34-0410-b5e6-96231b3b80d8
replacing the overly conservative checks that I had introduced recently to
deal with correctness issues. This makes a pretty noticable difference
in our testcases where reg_sequences are used. I've updated one test to
check that we no longer emit the unnecessary subreg moves.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105991 91177308-0d34-0410-b5e6-96231b3b80d8
- Rename ExactHazardRecognizer to PostRAHazardRecognizer and move its header to include to allow targets to extend it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105959 91177308-0d34-0410-b5e6-96231b3b80d8
clean-up to a catch-all after inlining, take into account that there could be
filter IDs as well. The presence of filters don't mean that the selector catches
anything. It's just metadata information.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105872 91177308-0d34-0410-b5e6-96231b3b80d8
This is a bit of a hack to make inline asm look more like call instructions.
It would be better to produce correct dead flags during isel.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105749 91177308-0d34-0410-b5e6-96231b3b80d8
%reg1025 = <sext> %reg1024
...
%reg1026 = SUBREG_TO_REG 0, %reg1024, 4
into this:
%reg1025 = <sext> %reg1024
...
%reg1027 = EXTRACT_SUBREG %reg1025, 4
%reg1026 = SUBREG_TO_REG 0, %reg1027, 4
The problem here is that SUBREG_TO_REG is there to assert that an implicit zext
occurs. It doesn't insert a zext instruction. If we allow the EXTRACT_SUBREG
here, it will give us the value after the <sext>, not the original value of
%reg1024 before <sext>.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105741 91177308-0d34-0410-b5e6-96231b3b80d8
register allocation.
Process all of the clobber lists at the end of the function, marking the
registers as used in MachineRegisterInfo.
This is necessary in case the calls clobber callee-saved registers (sic).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105473 91177308-0d34-0410-b5e6-96231b3b80d8
replace an OpA with a widened OpB, it is possible to get new uses of OpA due to CSE
when recursively updating nodes. Since OpA has been processed, the new uses are
not examined again. The patch checks if this occurred and it it did, updates the
new uses of OpA to use OpB.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105453 91177308-0d34-0410-b5e6-96231b3b80d8
Check that all the instructions are in the same basic block, that the
EXTRACT_SUBREGs write to the same subregs that are being extracted, and that
the source and destination registers are in the same regclass. Some of
these constraints can be relaxed with a bit more work. Jakob suggested
that the loop that checks for subregs when NewSubIdx != 0 should use the
"nodbg" iterator, so I made that change here, too.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105437 91177308-0d34-0410-b5e6-96231b3b80d8
