Delay outgoing register assignments to last.

The delayed stack protector feature which is currently used for SDAG (and thus
allows for more commonly generating tail calls) depends on being able to e

Delay outgoing register assignments to last.

The delayed stack protector feature which is currently used for SDAG (and thus
allows for more commonly generating tail calls) depends on being able to extract
the tail call into a separate return block. To do this it also has to extract
the vreg->physreg copies that set up the call's arguments, since if it doesn't
then the call inst ends up using undefined physregs in it's new spliced block.

SelectionDAG implementations can do this because they delay emitting register
copies until *after* the stack arguments are set up. GISel however just
processes and emits the arguments in IR order, so stack arguments always end up
last, and thus this breaks the code that looks for any register arg copies that
precede the call instruction.

This patch adds a thunk argument to the assignValueToReg() and custom assignment
hooks. For outgoing arguments, register assignments use this return param to
return a thunk that does the actual generating of the copies. We collect these
until all the outgoing stack assignments have been done and then execute them,
so that the copies (and perhaps some artifacts like G_SEXTs) are placed after
any stores.

Differential Revision: https://reviews.llvm.org/D110610

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[GlobalISel] Re-generate some call lowering tests with the new CHECK-NEXT behaviour.

Mips/GlobalISel: Use more standard call lowering infrastructure

This also fixes some missing implicit uses on call instructions, adds
missing G_ASSERT_SEXT/ZEXT annotations, and some missing outgoin

Mips/GlobalISel: Use more standard call lowering infrastructure

This also fixes some missing implicit uses on call instructions, adds
missing G_ASSERT_SEXT/ZEXT annotations, and some missing outgoing
sext/zexts. This also fixes not respecting tablegen requested type
promotions.

This starts treating f64 passed in i32 GPRs as a type of custom
assignment, which restores some previously XFAILed tests. This is due
to getNumRegistersForCallingConv returns a static value, but in this
case it is context dependent on other arguments.

Most of the ugliness is reproducing a hack CC_MipsO32 uses in
SelectionDAG. CC_MipsO32 depends on a bunch of vectors populated from
the original IR argument types in MipsCCState. The way this ends up
working in GlobalISel is it only ends up inspecting the most recently
added vector element. I'm pretty sure there are cleaner ways to do
this, but this seemed easier than fixing up the current DAG
handling. This is another case where it would be easier of the
CCAssignFns were passed the original type instead of only the
pre-legalized ones.

There's still a lot of junk here that shouldn't be necessary. This
also likely breaks big endian handling, but it wasn't complete/tested
anyway since the IRTranslator gives up on big endian targets.

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Mips: Mark special case calling convention handling as custom

The number of registers used for passing f64 in some cases is context
dependent, and thus getNumRegistersForCallingConv is sometimes
ina

Mips: Mark special case calling convention handling as custom

The number of registers used for passing f64 in some cases is context
dependent, and thus getNumRegistersForCallingConv is sometimes
inaccurate. For f64, it reports 1 but is sometimes split into 2 32-bit
registers.

For GlobalISel, the generic argument assignment code expects
getNumRegistersForCallingConv to return an accurate answer. Switch to
marking these arguments as custom so we can deal with this case as a
custom assignment rather.

This temporarily breaks a few globalisel tests which are fixed by a
future change to use more of the generic infrastructure.

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[MIPS GlobalISel] RegBankSelect G_MERGE_VALUES and G_UNMERGE_VALUES

Consider large operands in G_MERGE_VALUES and G_UNMERGE_VALUES as
Ambiguous during regbank selection.
Introducing new InstType Amb

[MIPS GlobalISel] RegBankSelect G_MERGE_VALUES and G_UNMERGE_VALUES

Consider large operands in G_MERGE_VALUES and G_UNMERGE_VALUES as
Ambiguous during regbank selection.
Introducing new InstType AmbiguousWithMergeOrUnmerge which will
allow us to recognize whether to narrow scalar or use s64:fprb.

This change exposed a bug when reusing data from TypeInfoForMF.
Thus when Instr is about to get destroyed (using narrow scalar)
clear its data in TypeInfoForMF. Internal data is saved based on
Instr's address, and it will no longer be valid.
Add detailed asserts for InstType and operand size.

Generate generic instructions instead of MIPS target instructions
during argument lowering and custom legalizer.
Select G_UNMERGE_VALUES and G_MERGE_VALUES when proper banks are
selected: {s32:gprb, s32:gprb, s64:fprb} for G_UNMERGE_VALUES and
{s64:fprb, s32:gprb, s32:gprb} for G_MERGE_VALUES.
Update tests. One improvement is when floating point argument in
gpr(or two gprs) gets passed to another function through gpr
unnecessary fpr-to-gpr moves are no longer generated.

Differential Revision: https://reviews.llvm.org/D74623

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[MIPS GlobalISel] Lower float and double arguments in registers

Lower float and double arguments in registers for MIPS32.
When float/double argument is passed through gpr registers
select appropriat

[MIPS GlobalISel] Lower float and double arguments in registers

Lower float and double arguments in registers for MIPS32.
When float/double argument is passed through gpr registers
select appropriate move instruction.

Differential Revision: https://reviews.llvm.org/D59642

llvm-svn: 356882

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