use-before-def. The problem comes up in code with multiple PHIs where
one PHI is being rewritten in terms of the other, but the other needs
to be casted first. LLVM rules requre the cast instruction to be
inserted after any PHI instructions, but when instructions were
inserted to replace the second PHI value with a function of the first,
they were ended up going before the cast instruction. Avoid this
problem by remembering the location of the cast instruction, when one
is needed, and inserting the expansion of the new value after it.
This fixes a bug that surfaced in 255.vortex on x86-64 when
instcombine was removed from the middle of the loop optimization
passes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51169 91177308-0d34-0410-b5e6-96231b3b80d8
Note, some of the code will be moved into target independent part of DAG combiner in a subsequent patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50918 91177308-0d34-0410-b5e6-96231b3b80d8
%ecx = op
store %cl<kill>, (addr)
(addr) = op %al
It's not safe to unfold the last operand and eliminate store even though %cl is marked kill. It's a sub-register use which means one of its super-register(s) may be used below.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50794 91177308-0d34-0410-b5e6-96231b3b80d8
the code being generated does not require an executable stack.
Also, add target-specific code to make use of this on Linux
on x86.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50634 91177308-0d34-0410-b5e6-96231b3b80d8
ffastmath mode. This fixes rdar://5902801, a miscompilation
of gcc.dg/builtins-8.c.
Bill, please pull this into Tak.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50523 91177308-0d34-0410-b5e6-96231b3b80d8
We now compile test2/test3 to:
_test2:
## InlineAsm Start
set %xmm0, %xmm1
## InlineAsm End
addps %xmm1, %xmm0
ret
_test3:
## InlineAsm Start
set %xmm0, %xmm1
## InlineAsm End
paddd %xmm1, %xmm0
ret
as expected.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50389 91177308-0d34-0410-b5e6-96231b3b80d8
towards PR2094. It now compiles the attached .ll file to:
_sad16_sse2:
movslq %ecx, %rax
## InlineAsm Start
%ecx %rdx %rax %rax %r8d %rdx %rsi
## InlineAsm End
## InlineAsm Start
set %eax
## InlineAsm End
ret
which is pretty decent for a 3 output, 4 input asm.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50386 91177308-0d34-0410-b5e6-96231b3b80d8
e.g.
vr1024<2> extract_subreg vr1025, 2
If vr1024 do not have the same register class as vr1025, it's not safe to coalesce this away. For example, vr1024 might be a GPR32 while vr1025 might be a GPR64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50385 91177308-0d34-0410-b5e6-96231b3b80d8
When choosing between constraints with multiple options,
like "ir", test to see if we can use the 'i' constraint and
go with that if possible. This produces more optimal ASM in
all cases (sparing a register and an instruction to load it),
and fixes inline asm like this:
void test () {
asm volatile (" %c0 %1 " : : "imr" (42), "imr"(14));
}
Previously we would dump "42" into a memory location (which
is ok for the 'm' constraint) which would cause a problem
because the 'c' modifier is not valid on memory operands.
Isn't it great how inline asm turns 'missed optimization'
into 'compile failed'??
Incidentally, this was the todo in
PowerPC/2007-04-24-InlineAsm-I-Modifier.ll
Please do NOT pull this into Tak.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50315 91177308-0d34-0410-b5e6-96231b3b80d8
On Darwin / Linux x86-32, v8i8, v4i16, v2i32 values are passed in MM[0-2].
On Darwin / Linux x86-32, v1i64 values are passed in memory.
On Darwin x86-64, v8i8, v4i16, v2i32 values are passed in XMM[0-7].
On Darwin x86-64, v1i64 values are passed in 64-bit GPRs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50257 91177308-0d34-0410-b5e6-96231b3b80d8
idea what this code (findNonImmUse) does, so I'm only guessing
that this is the right thing. It would be really really nice
if this had comments and perhaps switched to SmallPtrSet
(hint hint) :)
This fixes rdar://5886601, a crash on gcc.target/i386/sse4_1-pblendw.c
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50252 91177308-0d34-0410-b5e6-96231b3b80d8
argument. The x86-64 ABI requires the incoming value of %rdi to
be copied to %rax on exit from a function that is returning a
large C struct.
Also, add a README-X86-64 entry detailing the missed optimization
opportunity and proposing an alternative approach.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50075 91177308-0d34-0410-b5e6-96231b3b80d8
memcpy lowering code; this ensures that the size node has the desired
result type. This fixes a regression from r49572 with @llvm.memcpy.i64
on x86-32.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49761 91177308-0d34-0410-b5e6-96231b3b80d8
ScheduleDAG; they don't correspond to any actual instructions so they
don't need to be scheduled.
This fixes a bug where the EntryToken was being scheduled multiple
times in some cases, though it ended up not causing any trouble because
EntryToken doesn't expand into anything. With this fixed the schedulers
reliably schedule the expected number of units, so we can check this
with an assertion.
This requires a tweak to test/CodeGen/X86/loop-hoist.ll because it
ends up getting scheduled differently in a trivial way, though it was
enough to fool the prcontext+grep that the test does.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49701 91177308-0d34-0410-b5e6-96231b3b80d8
optimized x86-64 (and x86) calls so that they work (... at least for
my test cases).
Should fix the following problems:
Problem 1: When i introduced the optimized handling of arguments for
tail called functions (using a sequence of copyto/copyfrom virtual
registers instead of always lowering to top of the stack) i did not
handle byval arguments correctly e.g they did not work at all :).
Problem 2: On x86-64 after the arguments of the tail called function
are moved to their registers (which include ESI/RSI etc), tail call
optimization performs byval lowering which causes xSI,xDI, xCX
registers to be overwritten. This is handled in this patch by moving
the arguments to virtual registers first and after the byval lowering
the arguments are moved from those virtual registers back to
RSI/RDI/RCX.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49584 91177308-0d34-0410-b5e6-96231b3b80d8
on any current target and aren't optimized in DAGCombiner. Instead
of using intermediate nodes, expand the operations, choosing between
simple loads/stores, target-specific code, and library calls,
immediately.
Previously, the code to emit optimized code for these operations
was only used at initial SelectionDAG construction time; now it is
used at all times. This fixes some cases where rep;movs was being
used for small copies where simple loads/stores would be better.
This also cleans up code that checks for alignments less than 4;
let the targets make that decision instead of doing it in
target-independent code. This allows x86 to use rep;movs in
low-alignment cases.
Also, this fixes a bug that resulted in the use of rep;stos for
memsets of 0 with non-constant memory size when the alignment was
at least 4. It's better to use the library in this case, which
can be significantly faster when the size is large.
This also preserves more SourceValue information when memory
intrinsics are lowered into simple loads/stores.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49572 91177308-0d34-0410-b5e6-96231b3b80d8
MOVZQI2PQIrr. This would be better handled as a dag combine
(with the goal of eliminating the bitconvert) but I don't know
how to do that safely. Thoughts welcome.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49463 91177308-0d34-0410-b5e6-96231b3b80d8
If it cannot be expanded, it will keep the old behaviour and try to shrink the constant.
Part of enhancement for PR2191.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49280 91177308-0d34-0410-b5e6-96231b3b80d8
EH info for these functions causes the tests to fail for
random reasons (e.g. looking for 'or' or counting lines
with asm-printer; labels count as lines.)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49003 91177308-0d34-0410-b5e6-96231b3b80d8
llvm's output .s files will go through gcc -std=c99
without triggering preprocesser errors. Approach
suggested by Daveed Vandevoorde.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48808 91177308-0d34-0410-b5e6-96231b3b80d8
other things, this allows the scheduler to unfold a load operand
in the 2008-01-08-SchedulerCrash.ll testcase, so it now successfully
clones the comparison to avoid a pushf+popf.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48777 91177308-0d34-0410-b5e6-96231b3b80d8
This allows us to compile fp-stack-2results.ll into:
_test:
fldz
fld1
ret
which returns 1 in ST(0) and 0 in ST(1). This is needed for x86-64
_Complex long double.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48632 91177308-0d34-0410-b5e6-96231b3b80d8
1. If part of a register is re-defined, an implicit kill and an implicit def are added to denote read / mod / write. However, this should only be necessary if the register is actually read later. This is a performance issue.
2. If a sub-register is being defined, and it doesn't have a previous use, do not add a implicit kill to the last use of a super-register:
= EAX, AX<imp-use,kill>
...
AX =
In this case, EAX is live but AX is killed, this is wrong and will cause the coalescer to do bad things.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48521 91177308-0d34-0410-b5e6-96231b3b80d8
the automated CallingConv code to handle return values typically
don't support multiple return values.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48265 91177308-0d34-0410-b5e6-96231b3b80d8
Judging from the checking comments this is intentional,
so add the flag (makes them pass on non-x86 host).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48157 91177308-0d34-0410-b5e6-96231b3b80d8
If ALR and BLR overlaps and end of BLR extends beyond end of ALR, e.g.
A = or A, B
...
B = A
...
C = A<kill>
...
= B
then do not add kills of A to the newly created B interval.
- Also fix some kill info update bug.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48141 91177308-0d34-0410-b5e6-96231b3b80d8
an RFP register class.
Teach ScheduleDAG how to handle CopyToReg with different src/dst
reg classes.
This allows us to compile trivial inline asms that expect stuff
on the top of x87-fp stack.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48107 91177308-0d34-0410-b5e6-96231b3b80d8
in different register classes, e.g. copy of ST(0) to RFP*. This gets
some really trivial inline asm working that plops things on the top of
stack (PR879)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48105 91177308-0d34-0410-b5e6-96231b3b80d8
into a vector of zeros or undef, and when the top part is obviously
zero, we can just use movd + shuffle. This allows us to compile
vec_set-B.ll into:
_test3:
movl $1234567, %eax
andl 4(%esp), %eax
movd %eax, %xmm0
ret
instead of:
_test3:
subl $28, %esp
movl $1234567, %eax
andl 32(%esp), %eax
movl %eax, (%esp)
movl $0, 4(%esp)
movq (%esp), %xmm0
addl $28, %esp
ret
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48090 91177308-0d34-0410-b5e6-96231b3b80d8
_test3:
movd %rdi, %xmm1
#IMPLICIT_DEF %xmm0
punpcklqdq %xmm1, %xmm0
ret
instead of:
_test3:
#IMPLICIT_DEF %rax
movd %rax, %xmm0
movd %rdi, %xmm1
punpcklqdq %xmm1, %xmm0
ret
This is still not ideal. There is no reason to two xmm regs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48058 91177308-0d34-0410-b5e6-96231b3b80d8
except ppc long double. This allows us to shrink constant pool
entries for x86 long double constants, which in turn allows us to
use flds/fldl instead of fldt.
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For x86, if sse2 is available, it's not a good idea since cvtss2sd is slower than a movsd load and it prevents load folding. On x87, it's important to shrink fp constant since fldt is very expensive.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47931 91177308-0d34-0410-b5e6-96231b3b80d8
stack slot and store if the SINT_TO_FP is actually legal. This allows
us to compile:
double a(double b) {return (unsigned)b;}
to:
_a:
cvttsd2siq %xmm0, %rax
movl %eax, %eax
cvtsi2sdq %rax, %xmm0
ret
instead of:
_a:
subq $8, %rsp
cvttsd2siq %xmm0, %rax
movl %eax, %eax
cvtsi2sdq %rax, %xmm0
addq $8, %rsp
ret
crazy.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47660 91177308-0d34-0410-b5e6-96231b3b80d8
_test:
movl %edi, %eax
ret
instead of:
_test:
movl $4294967295, %ecx
movq %rdi, %rax
andq %rcx, %rax
ret
It would be great to write this as a Pat pattern that used subregs
instead of a 'pseudo' instruction, but I don't know how to do that
in td files.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47658 91177308-0d34-0410-b5e6-96231b3b80d8
vr1 = extract_subreg vr2, 3
...
vr3 = extract_subreg vr1, 2
The end result is vr3 is equal to vr2 with subidx 2.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47592 91177308-0d34-0410-b5e6-96231b3b80d8
instead of with mmx registers. This horribleness is apparently
done by gcc to avoid having to insert emms in places that really
should have it. This is the second half of rdar://5741668.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47474 91177308-0d34-0410-b5e6-96231b3b80d8
GCC apparently does this, and code depends on not having to do
emms when this happens. This is x86-64 only so far, second half
should handle x86-32.
rdar://5741668
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47470 91177308-0d34-0410-b5e6-96231b3b80d8
any, we force sdisel to do all regalloc for an asm. This
leads to gross but correct codegen.
This fixes the rest of PR2078.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47454 91177308-0d34-0410-b5e6-96231b3b80d8
inline asms.
Fix PR2078 by marking aliases of registers used when a register is
marked used. This prevents EAX from being allocated when AX is listed
in the clobber set for the asm.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47426 91177308-0d34-0410-b5e6-96231b3b80d8
- X86 now normalize SCALAR_TO_VECTOR to (BIT_CONVERT (v4i32 SCALAR_TO_VECTOR)). Get rid of X86ISD::S2VEC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47290 91177308-0d34-0410-b5e6-96231b3b80d8
has plain one-result scalar integer multiplication instructions.
This avoids expanding such instructions into MUL_LOHI sequences that
must be special-cased at isel time, and avoids the problem with that
code that provented memory operands from being folded.
This fixes PR1874, addressesing the most common case. The uncommon
cases of optimizing multiply-high operations will require work
in DAGCombiner.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47277 91177308-0d34-0410-b5e6-96231b3b80d8
node as soon as we create it in SDISel. Previously we would lower it in
legalize. The problem with this is that it only exposes the argument
loads implied by FORMAL_ARGUMENTs after legalize, so that only dag combine 2
can hack on them. This causes us to miss some optimizations because
datatype expansion also happens here.
Exposing the loads early allows us to do optimizations on them. For example
we now compile arg-cast.ll to:
_foo:
movl $2147483647, %eax
andl 8(%esp), %eax
ret
where we previously produced:
_foo:
subl $12, %esp
movsd 16(%esp), %xmm0
movsd %xmm0, (%esp)
movl $2147483647, %eax
andl 4(%esp), %eax
addl $12, %esp
ret
It might also make sense to do this for ISD::CALL nodes, which have implicit
stores on many targets.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47054 91177308-0d34-0410-b5e6-96231b3b80d8
registers if used by a bitconvert or using a bitconvert. This allows us to
avoid constant pool loads and use cheaper integer instructions when the
values come from or end up in integer regs anyway. For example, we now
compile CodeGen/X86/fp-in-intregs.ll to:
_test1:
movl $2147483648, %eax
xorl 4(%esp), %eax
ret
_test2:
movl $1065353216, %eax
orl 4(%esp), %eax
andl $3212836864, %eax
ret
Instead of:
_test1:
movss 4(%esp), %xmm0
xorps LCPI2_0, %xmm0
movd %xmm0, %eax
ret
_test2:
movss 4(%esp), %xmm0
andps LCPI3_0, %xmm0
movss LCPI3_1, %xmm1
andps LCPI3_2, %xmm1
orps %xmm0, %xmm1
movd %xmm1, %eax
ret
bitconverts can happen due to various calling conventions that require
fp values to passed in integer regs in some cases, e.g. when returning
a complex.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46414 91177308-0d34-0410-b5e6-96231b3b80d8
This case returns the value in ST(0) and then has to convert it to an SSE
register. This causes significant codegen ugliness in some cases. For
example in the trivial fp-stack-direct-ret.ll testcase we used to generate:
_bar:
subl $28, %esp
call L_foo$stub
fstpl 16(%esp)
movsd 16(%esp), %xmm0
movsd %xmm0, 8(%esp)
fldl 8(%esp)
addl $28, %esp
ret
because we move the result of foo() into an XMM register, then have to
move it back for the return of bar.
Instead of hacking ever-more special cases into the call result lowering code
we take a much simpler approach: on x86-32, fp return is modeled as always
returning into an f80 register which is then truncated to f32 or f64 as needed.
Similarly for a result, we model it as an extension to f80 + return.
This exposes the truncate and extensions to the dag combiner, allowing target
independent code to hack on them, eliminating them in this case. This gives
us this code for the example above:
_bar:
subl $12, %esp
call L_foo$stub
addl $12, %esp
ret
The nasty aspect of this is that these conversions are not legal, but we want
the second pass of dag combiner (post-legalize) to be able to hack on them.
To handle this, we lie to legalize and say they are legal, then custom expand
them on entry to the isel pass (PreprocessForFPConvert). This is gross, but
less gross than the code it is replacing :)
This also allows us to generate better code in several other cases. For
example on fp-stack-ret-conv.ll, we now generate:
_test:
subl $12, %esp
call L_foo$stub
fstps 8(%esp)
movl 16(%esp), %eax
cvtss2sd 8(%esp), %xmm0
movsd %xmm0, (%eax)
addl $12, %esp
ret
where before we produced (incidentally, the old bad code is identical to what
gcc produces):
_test:
subl $12, %esp
call L_foo$stub
fstpl (%esp)
cvtsd2ss (%esp), %xmm0
cvtss2sd %xmm0, %xmm0
movl 16(%esp), %eax
movsd %xmm0, (%eax)
addl $12, %esp
ret
Note that we generate slightly worse code on pr1505b.ll due to a scheduling
deficiency that is unrelated to this patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46307 91177308-0d34-0410-b5e6-96231b3b80d8
1. Legalize now always promotes truncstore of i1 to i8.
2. Remove patterns and gunk related to truncstore i1 from targets.
3. Rename the StoreXAction stuff to TruncStoreAction in TLI.
4. Make the TLI TruncStoreAction table a 2d table to handle from/to conversions.
5. Mark a wide variety of invalid truncstores as such in various targets, e.g.
X86 currently doesn't support truncstore of any of its integer types.
6. Add legalize support for truncstores with invalid value input types.
7. Add a dag combine transform to turn store(truncate) into truncstore when
safe.
The later allows us to compile CodeGen/X86/storetrunc-fp.ll to:
_foo:
fldt 20(%esp)
fldt 4(%esp)
faddp %st(1)
movl 36(%esp), %eax
fstps (%eax)
ret
instead of:
_foo:
subl $4, %esp
fldt 24(%esp)
fldt 8(%esp)
faddp %st(1)
fstps (%esp)
movl 40(%esp), %eax
movss (%esp), %xmm0
movss %xmm0, (%eax)
addl $4, %esp
ret
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46140 91177308-0d34-0410-b5e6-96231b3b80d8
and the spill is its kill. However, if the local allocator has determined the
register has not been modified (possible when its value was reloaded), it would
not issue a restore. In that case, mark the last use of the virtual register as
kill.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46111 91177308-0d34-0410-b5e6-96231b3b80d8
It's not safe to use the two value CombineTo variant to combine away a dead load.
e.g.
v1, chain2 = load chain1, loc
v2, chain3 = load chain2, loc
v3 = add v2, c
Now we replace use of v1 with undef, use of chain2 with chain1.
ReplaceAllUsesWith() will iterate through uses of the first load and update operands:
v1, chain2 = load chain1, loc
v2, chain3 = load chain1, loc
v3 = add v2, c
Now the second load is the same as the first load, SelectionDAG cse will ensure
the use of second load is replaced with the first load.
v1, chain2 = load chain1, loc
v3 = add v1, c
Then v1 is replaced with undef and bad things happen.
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it should work, but I have no machine to test
it on. Committed because it will at least
cause no harm, and maybe someone can test it
for me!
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