- Change register allocation hint to a pair of unsigned integers. The hint type is zero (which means prefer the register specified as second part of the pair) or entirely target dependent.
- Allow targets to specify alternative register allocation orders based on allocation hint.
Part 2.
- Use the register allocation hint system to implement more aggressive load / store multiple formation.
- Aggressively form LDRD / STRD. These are formed *before* register allocation. It has to be done this way to shorten live interval of base and offset registers. e.g.
v1025 = LDR v1024, 0
v1026 = LDR v1024, 0
=>
v1025,v1026 = LDRD v1024, 0
If this transformation isn't done before allocation, v1024 will overlap v1025 which means it more difficult to allocate a register pair.
- Even with the register allocation hint, it may not be possible to get the desired allocation. In that case, the post-allocation load / store multiple pass must fix the ldrd / strd instructions. They can either become ldm / stm instructions or back to a pair of ldr / str instructions.
This is work in progress, not yet enabled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73381 91177308-0d34-0410-b5e6-96231b3b80d8
consecutive addresses togther. This makes it easier for the post-allocation pass
to form ldm / stm.
This is step 1. We are still missing a lot of ldm / stm opportunities because
of register allocation are not done in the desired order. More enhancements
coming.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73291 91177308-0d34-0410-b5e6-96231b3b80d8
out of sync with regular cc.
The only difference between the tail call cc and the normal
cc was that one parameter register - R9 - was reserved for
calling functions through a function pointer. After time the
tail call cc has gotten out of sync with the regular cc.
We can use R11 which is also caller saved but not used as
parameter register for potential function pointers and
remove the special tail call cc on x86-64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73233 91177308-0d34-0410-b5e6-96231b3b80d8
on x86 to handle more cases. Fix a bug in said code that would cause it
to read past the end of an object. Rewrite the code in
SelectionDAGLegalize::ExpandBUILD_VECTOR to be a bit more general.
Remove PerformBuildVectorCombine, which is no longer necessary with
these changes. In addition to simplifying the code, with this change,
we can now catch a few more cases of consecutive loads.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73012 91177308-0d34-0410-b5e6-96231b3b80d8
nodes for vectors with an i16 element type. Add an optimization for
building a vector which is all zeros/undef except for the bottom
element, where the bottom element is an i8 or i16.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72988 91177308-0d34-0410-b5e6-96231b3b80d8
build vectors with i64 elements will only appear on 32b x86 before legalize.
Since vector widening occurs during legalize, and produces i64 build_vector
elements, the dag combiner is never run on these before legalize splits them
into 32b elements.
Teach the build_vector dag combine in x86 back end to recognize consecutive
loads producing the low part of the vector.
Convert the two uses of TLI's consecutive load recognizer to pass LoadSDNodes
since that was required implicitly.
Add a testcase for the transform.
Old:
subl $28, %esp
movl 32(%esp), %eax
movl 4(%eax), %ecx
movl %ecx, 4(%esp)
movl (%eax), %eax
movl %eax, (%esp)
movaps (%esp), %xmm0
pmovzxwd %xmm0, %xmm0
movl 36(%esp), %eax
movaps %xmm0, (%eax)
addl $28, %esp
ret
New:
movl 4(%esp), %eax
pmovzxwd (%eax), %xmm0
movl 8(%esp), %eax
movaps %xmm0, (%eax)
ret
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integer and floating-point opcodes, introducing
FAdd, FSub, and FMul.
For now, the AsmParser, BitcodeReader, and IRBuilder all preserve
backwards compatability, and the Core LLVM APIs preserve backwards
compatibility for IR producers. Most front-ends won't need to change
immediately.
This implements the first step of the plan outlined here:
http://nondot.org/sabre/LLVMNotes/IntegerOverflow.txt
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Update code generator to use this attribute and remove DisableRedZone target option.
Update llc to set this attribute when -disable-red-zone command line option is used.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72894 91177308-0d34-0410-b5e6-96231b3b80d8
relocation model on x86-64. Higher level logic should override
the relocation model to PIC on x86_64-apple-darwin.
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e.g.
orl $65536, 8(%rax)
=>
orb $1, 10(%rax)
Since narrowing is not always a win, e.g. i32 -> i16 is a loss on x86, dag combiner consults with the target before performing the optimization.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72507 91177308-0d34-0410-b5e6-96231b3b80d8
The DAGCombiner created a negative shiftamount, stored in an
unsigned variable. Later the optimizer eliminated the shift entirely as being
undefined.
Example: (srl (shl X, 56) 48). ShiftAmt is 4294967288.
Fix it by checking that the shiftamount is positive, and storing in a signed
variable.
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and it wasn't generating calls through @PLT for these functions.
hasLocalLinkage() is now false for available_externally,
I attempted to fix the inliner and dce to handle available_externally properly.
It passed make check.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72328 91177308-0d34-0410-b5e6-96231b3b80d8
code in preparation for code generation. The main thing it does
is handle the case when eh.exception calls (and, in a future
patch, eh.selector calls) are far away from landing pads. Right
now in practice you only find eh.exception calls close to landing
pads: either in a landing pad (the common case) or in a landing
pad successor, due to loop passes shifting them about. However
future exception handling improvements will result in calls far
from landing pads:
(1) Inlining of rewinds. Consider the following case:
In function @f:
...
invoke @g to label %normal unwind label %unwinds
...
unwinds:
%ex = call i8* @llvm.eh.exception()
...
In function @g:
...
invoke @something to label %continue unwind label %handler
...
handler:
%ex = call i8* @llvm.eh.exception()
... perform cleanups ...
"rethrow exception"
Now inline @g into @f. Currently this is turned into:
In function @f:
...
invoke @something to label %continue unwind label %handler
...
handler:
%ex = call i8* @llvm.eh.exception()
... perform cleanups ...
invoke "rethrow exception" to label %normal unwind label %unwinds
unwinds:
%ex = call i8* @llvm.eh.exception()
...
However we would like to simplify invoke of "rethrow exception" into
a branch to the %unwinds label. Then %unwinds is no longer a landing
pad, and the eh.exception call there is then far away from any landing
pads.
(2) Using the unwind instruction for cleanups.
It would be nice to have codegen handle the following case:
invoke @something to label %continue unwind label %run_cleanups
...
handler:
... perform cleanups ...
unwind
This requires turning "unwind" into a library call, which
necessarily takes a pointer to the exception as an argument
(this patch also does this unwind lowering). But that means
you are using eh.exception again far from a landing pad.
(3) Bugpoint simplifications. When bugpoint is simplifying
exception handling code it often generates eh.exception calls
far from a landing pad, which then causes codegen to assert.
Bugpoint then latches on to this assertion and loses sight
of the original problem.
Note that it is currently rare for this pass to actually do
anything. And in fact it normally shouldn't do anything at
all given the code coming out of llvm-gcc! But it does fire
a few times in the testsuite. As far as I can see this is
almost always due to the LoopStrengthReduce codegen pass
introducing pointless loop preheader blocks which are landing
pads and only contain a branch to another block. This other
block contains an eh.exception call. So probably by tweaking
LoopStrengthReduce a bit this can be avoided.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72276 91177308-0d34-0410-b5e6-96231b3b80d8
build an integer and cast that to a float. This fixes a crash
caused by trying to split an f32 into two f16's.
This changes the behavior in test/CodeGen/XCore/fneg.ll because that
testcase now triggers a DAGCombine which converts the fneg into an integer
operation. If someone is interested, it's probably possible to tweak
the test to generate an actual fneg.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72162 91177308-0d34-0410-b5e6-96231b3b80d8
