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
registers it defines then interfere with an existing preg live range.
For instance, if we had something like these machine instructions:
BB#0
... = imul ... EFLAGS<imp-def,dead>
test ..., EFLAGS<imp-def>
jcc BB#2 EFLAGS<imp-use>
BB#1
... ; fallthrough to BB#2
BB#2
... ; No code that defines EFLAGS
jcc ... EFLAGS<imp-use>
Machine sink will come along, see that imul implicitly defines EFLAGS, but
because it's "dead", it assumes that it can move imul into BB#2. But when it
does, imul's "dead" imp-def of EFLAGS is raised from the dead (a zombie) and
messes up the condition code for the jump (and pretty much anything else which
relies upon it being correct).
The solution is to know which pregs are live going into a basic block. However,
that information isn't calculated at this point. Nor does the LiveVariables pass
take into account non-allocatable physical registers. In lieu of this, we do a
*very* conservative pass through the basic block to determine if a preg is live
coming out of it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105387 91177308-0d34-0410-b5e6-96231b3b80d8
expansion is the same as that used by LegalizeDAG.
The resulting code sucks in terms of performance/codesize on x86-32 for a
64-bit operation; I haven't looked into whether different expansions might be
better in general.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105378 91177308-0d34-0410-b5e6-96231b3b80d8
spills and reloads.
This means that a partial define of a register causes a reload so the other
parts of the register are preserved.
The reload can be prevented by adding an <imp-def> operand for the full
register. This is already done by the coalescer and live interval analysis where
relevant.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105369 91177308-0d34-0410-b5e6-96231b3b80d8
register updates.
These operands tell the spiller that the other parts of the partially defined
register are don't-care, and a reload is not necessary.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105361 91177308-0d34-0410-b5e6-96231b3b80d8
instruction defines subregisters.
Any existing subreg indices on the original instruction are preserved or
composed with the new subreg index.
Also substitute multiple operands mentioning the original register by using the
new MachineInstr::substituteRegister() function. This is necessary because there
will soon be <imp-def> operands added to non read-modify-write partial
definitions. This instruction:
%reg1234:foo = FLAP %reg1234<imp-def>
will reMaterialize(%reg3333, bar) like this:
%reg3333:bar-foo = FLAP %reg333:bar<imp-def>
Finally, replace the TargetRegisterInfo pointer argument with a reference to
indicate that it cannot be NULL.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105358 91177308-0d34-0410-b5e6-96231b3b80d8
backends and removes the virtual declaration. With that out of the way
I should be able to cleanup one backend at a time.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105321 91177308-0d34-0410-b5e6-96231b3b80d8
The comment about ordering of subreg indices is no longer true.
This exposed a bug in the new substVirtReg method that is also fixed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105294 91177308-0d34-0410-b5e6-96231b3b80d8
handle structs passed by value via an extract/insert pair, as a bitcast
won't work on a struct. rdar://7742824
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105280 91177308-0d34-0410-b5e6-96231b3b80d8
that are too large. This causes the freebsd bootloader to be too
large apparently.
It's unclear if this should be an -Os or -Oz thing. Thoughts welcome.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105228 91177308-0d34-0410-b5e6-96231b3b80d8
shouldn't have a TargetLoweringInfo member. And FunctionLoweringInfo::set
doesn't needs its EnableFastISel argument.
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implementation that is correct for most targets. Tablegen will override where
needed.
Add MachineOperand::subst{Virt,Phys}Reg methods that correctly handle existing
subreg indices when sustituting registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104985 91177308-0d34-0410-b5e6-96231b3b80d8
optimization level.
This only really affects llc for now because both the llvm-gcc and clang front
ends override the default register allocator. I intend to remove that code later.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104904 91177308-0d34-0410-b5e6-96231b3b80d8
implementing pop with a linear search for a "best" element. The priority
queue was a neat idea, but in practice the comparison functions depend
on dynamic information.
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If you have a setjmp/longjmp situation, it's possible for stack slot coloring to
reuse a stack slot before it's really dead. For instance, if we have something
like this:
1: y = g;
x = sigsetjmp(env, 0);
switch (x) {
case 1:
/* ... */
goto run;
case 0:
run:
do_run(); /* marked as "no return" */
break;
case 3:
if (...) {
/* ... */
goto run;
}
/* ... */
break;
}
2: g = y;
"y" may be put onto the stack, so the expression "g = y" is relying upon the
fact that the stack slot containing "y" isn't modified between (1) and (2). But
it can be, because of the "no return" calls in there. A longjmp might come back
with 3, modify the stack slot, and then go to case 0. And it's perfectly
acceptable to reuse the stack slot there because there's no CFG flow from case 3
to (2).
The fix is to disable certain optimizations in these situations. Ideally, we'd
disable them for all "returns twice" functions. But we don't support that
attribute. Check for "setjmp" and "sigsetjmp" instead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104640 91177308-0d34-0410-b5e6-96231b3b80d8
Mon Ping provided; unfortunately bugpoint failed to
reduce it, but I think it's important to have a test for
this in the suite. 8023512.
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so that it will continue to test what it was meant to test when I commit a
separate change for better support of BUILD_VECTOR and VECTOR_SHUFFLE for Neon.
Fix a DAG combiner crash exposed by this test change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104380 91177308-0d34-0410-b5e6-96231b3b80d8
that are aliases of the specified register.
- Rename modifiesRegister to definesRegister since it's looking a def of the
specific register or one of its super-registers. It's not looking for def of a
sub-register or alias that could change the specified register.
- Added modifiesRegister to look for defs of aliases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104377 91177308-0d34-0410-b5e6-96231b3b80d8
reads or writes a register.
This takes partial redefines and undef uses into account.
Don't actually use it yet. That caused miscompiles.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104372 91177308-0d34-0410-b5e6-96231b3b80d8
definitions of the virtual register.
This happens when spilling the registers produced by REG_SEQUENCE:
%reg1047:5<def>, %reg1047:6<def>, %reg1047:7<def> = VLD3d8 %reg1033, 0, pred:14, pred:%reg0
The rewriter would spill the register multiple times, dead store elimination
tried to keep up, but ended up cutting the branch it was sitting on.
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<imp-def> operand for the full register. This ensures that the full physical
register is marked live after register allocation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104320 91177308-0d34-0410-b5e6-96231b3b80d8
pipeline stall. It's useful for targets like ARM cortex-a8. NEON has a lot
of long latency instructions so a strict register pressure reduction
scheduler does not work well.
Early experiments show this speeds up some NEON loops by over 30%.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104216 91177308-0d34-0410-b5e6-96231b3b80d8
test/Codegen/ARM/reg_sequence.ll but it doesn't affect the generated code
because the coalescer cleans it up. Radar 7998853.
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A partial redef now triggers a reload if required. Also don't add
<imp-def,dead> operands for physical superregisters.
Kill flags are still treated as full register kills, and <imp-use,kill> operands
are added for physical superregisters as before.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104167 91177308-0d34-0410-b5e6-96231b3b80d8
partial redefines.
We are going to treat a partial redefine of a virtual register as a
read-modify-write:
%reg1024:6 = OP
Unless the register is fully clobbered:
%reg1024:6 = OP, %reg1024<imp-def>
MachineInstr::readsVirtualRegister() knows the difference. The first case is a
read, the second isn't.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104149 91177308-0d34-0410-b5e6-96231b3b80d8
lowering REG_SEQUENCE instructions.
Insert copies for REG_SEQUENCE sources not killed to avoid breaking later passes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104146 91177308-0d34-0410-b5e6-96231b3b80d8
need to be promoted. The BUILD_VECTOR and EXTRACT_VECTOR_ELT nodes generated
here already allow the promoted type to be used without further changes, so
just do the promotion. This fixes part of pr7167.
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The trouble arises when the result of a vector cmp + sext is then and'ed with all ones. Instcombine will turn it into a vector cmp + zext, dag combiner will miss turning it into a vsetcc and hell breaks loose after that.
Teach dag combine to turn a vector cpm + zest into a vsetcc + and 1. This fixes rdar://7923010.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104094 91177308-0d34-0410-b5e6-96231b3b80d8
- Change the logic DisableFramePointerElim() to check for the
-disable-non-leaf-fp-elim before -disable-fp-elim.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103990 91177308-0d34-0410-b5e6-96231b3b80d8
This fixes the miscompilations of MultiSource/Applications/JM/l{en,de}cod.
Clang now successfully self hosts in a debug build with the fast register allocator.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103975 91177308-0d34-0410-b5e6-96231b3b80d8
While that approach works wonders for register pressure, it tends to break
everything.
This should unbreak the arm-linux builder and fix a number of miscompilations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103946 91177308-0d34-0410-b5e6-96231b3b80d8
out aliases when allocating. Clean up allocVirtReg().
Use calcSpillCost() to allow more aggressive hinting. Now the hint is always
taken unless blocked by a reserved register. This leads to more coalescing,
lower register pressure, and less spilling.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103939 91177308-0d34-0410-b5e6-96231b3b80d8
This is safe to do because the physreg has been marked UsedInInstr and the kill flag will be set on the last operand using the virtreg if there are more then one.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103933 91177308-0d34-0410-b5e6-96231b3b80d8
Debug code doesn't use callee saved registers anyway, and the code is simpler this way. Now spillVirtReg always kills, and the isKill parameter is not needed.
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The implementation in LegalizeIntegerTypes to handle this as
sint64->float + appropriate power of 2 is subject to double rounding,
considered incorrect by numerics people. Use this implementation only
when it is safe. This leads to using library calls in some cases
that produced inline code before, but it's correct now.
(EVTToAPFloatSemantics belongs somewhere else, any suggestions?)
Add a correctly rounding (though not particularly fast) conversion
that uses X87 80-bit computations for x86-32.
7885399, 5901940. This shows up in gcc.c-torture/execute/ieee/rbug.c
in the gcc testsuite on some platforms.
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a condition's grouping. Every other use of Allocatable.test(Hint) groups it the
same way as it is indented, so move the parentheses to agree with that
grouping.
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When working top-down in a basic block, substituting physregs for virtregs, the use-def chains are kept up to date. That means we can recognize a virtreg kill by the use-def chain becoming empty.
This makes the fast allocator independent of incoming kill flags.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103866 91177308-0d34-0410-b5e6-96231b3b80d8
instructions.
e.g.
%reg1026<def> = VLDMQ %reg1025<kill>, 260, pred:14, pred:%reg0
%reg1027<def> = EXTRACT_SUBREG %reg1026, 6
%reg1028<def> = EXTRACT_SUBREG %reg1026<kill>, 5
...
%reg1029<def> = REG_SEQUENCE %reg1028<kill>, 5, %reg1027<kill>, 6, %reg1028, 7, %reg1027, 8, %reg1028, 9, %reg1027, 10, %reg1030<kill>, 11, %reg1032<kill>, 12
After REG_SEQUENCE is eliminated, we are left with:
%reg1026<def> = VLDMQ %reg1025<kill>, 260, pred:14, pred:%reg0
%reg1029:6<def> = EXTRACT_SUBREG %reg1026, 6
%reg1029:5<def> = EXTRACT_SUBREG %reg1026<kill>, 5
The regular coalescer will not be able to coalesce reg1026 and reg1029 because it doesn't
know how to combine sub-register indices 5 and 6. Now 2-address pass will consult the
target whether sub-registers 5 and 6 of reg1026 can be combined to into a larger
sub-register (or combined to be reg1026 itself as is the case here). If it is possible,
it will be able to replace references of reg1026 with reg1029 + the larger sub-register
index.
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the variable actually tracks.
N.B., several back-ends are using "HasCalls" as being synonymous for something
that adjusts the stack. This isn't 100% correct and should be looked into.
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- Kill is implicit when use and def registers are identical.
- Only virtual registers can differ.
Add a -verify-fast-regalloc to run the verifier before the fast allocator.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103797 91177308-0d34-0410-b5e6-96231b3b80d8
-filetype=obj test, and -filetype=obj leaks a few objects. Added a FIXME, we
need to sort out the ownership model for the various MC objects.
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This loop is quadratic in the capacity for a DenseMap:
while(!map.empty())
map.erase(map.begin());
Instead we now do a normal begin() - end() iteration followed by map.clear().
That also has the nice sideeffect of shrinking the map capacity on demand.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103747 91177308-0d34-0410-b5e6-96231b3b80d8
Now, the .linkonce directive is emitted as part of MCSectionCOFF::PrintSwitchToSection instead of AsmPrinter::EmitLinkage since it is an attribute of the section the symbol was placed into not the symbol itself.
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