The previous change to local live range allocation also suppressed
eviction of local ranges. In rare cases, this could result in more
expensive register choices. This commit actually revives a feature
that I added long ago: check if live ranges can be reassigned before
eviction. But now it only happens in rare cases of evicting a local
live range because another local live range wants a cheaper register.
The benefit is improved code size for some benchmarks on x86 and armv7.
I measured no significant compile time increase and performance
changes are noise.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187140 91177308-0d34-0410-b5e6-96231b3b80d8
Also avoid locals evicting locals just because they want a cheaper register.
Problem: MI Sched knows exactly how many registers we have and assumes
they can be colored. In cases where we have large blocks, usually from
unrolled loops, greedy coloring fails. This is a source of
"regressions" from the MI Scheduler on x86. I noticed this issue on
x86 where we have long chains of two-address defs in the same live
range. It's easy to see this in matrix multiplication benchmarks like
IRSmk and even the unit test misched-matmul.ll.
A fundamental difference between the LLVM register allocator and
conventional graph coloring is that in our model a live range can't
discover its neighbors, it can only verify its neighbors. That's why
we initially went for greedy coloring and added eviction to deal with
the hard cases. However, for singly defined and two-address live
ranges, we can optimally color without visiting neighbors simply by
processing the live ranges in instruction order.
Other beneficial side effects:
It is much easier to understand and debug regalloc for large blocks
when the live ranges are allocated in order. Yes, global allocation is
still very confusing, but it's nice to be able to comprehend what
happened locally.
Heuristics could be added to bias register assignment based on
instruction locality (think late register pairing, banks...).
Intuituvely this will make some test cases that are on the threshold
of register pressure more stable.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187139 91177308-0d34-0410-b5e6-96231b3b80d8
For two intrinsics 'llvm.nvvm.texsurf.handle' and 'llvm.nvvm.texsurf.handle.internal',
TableGen was emitting matching code like:
if (Name.startswith("llvm.nvvm.texsurf.handle")) ...
if (Name.startswith("llvm.nvvm.texsurf.handle.internal")) ...
We can never match "llvm.nvvm.texsurf.handle.internal" here because it will
always be erroneously matched by the first condition.
The fix is to sort the intrinsic names and emit them in reverse order.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187119 91177308-0d34-0410-b5e6-96231b3b80d8
Before the patch we took advantage of the fact that the compare and
branch are glued together in the selection DAG and fused them together
(where possible) while emitting them. This seemed to work well in practice.
However, fusing the compare so early makes it harder to remove redundant
compares in cases where CC already has a suitable value. This patch
therefore uses the peephole analyzeCompare/optimizeCompareInstr pair of
functions instead.
No behavioral change intended, but it paves the way for a later patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187116 91177308-0d34-0410-b5e6-96231b3b80d8
As with the stores, these instructions can trap when the condition is false,
so they are only used for things like (cond ? x : *ptr).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187112 91177308-0d34-0410-b5e6-96231b3b80d8
These instructions are allowed to trap even if the condition is false,
so for now they are only used for "*ptr = (cond ? x : *ptr)"-style
constructs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187111 91177308-0d34-0410-b5e6-96231b3b80d8
Make sure the context and type fields are MDNodes. We will generate
verification errors if those fields are non-empty strings.
Fix testing cases to make them pass the verifier.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187106 91177308-0d34-0410-b5e6-96231b3b80d8
The language reference says that:
"If a symbol appears in the @llvm.used list, then the compiler,
assembler, and linker are required to treat the symbol as if there is
a reference to the symbol that it cannot see"
Since even the linker cannot see the reference, we must assume that
the reference can be using the symbol table. For example, a user can add
__attribute__((used)) to a debug helper function like dump and use it from
a debugger.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187103 91177308-0d34-0410-b5e6-96231b3b80d8
There's no need to specify a flag to omit frame pointer elimination on non-leaf
nodes...(Honestly, I can't parse that option out.) Use the function attribute
stuff instead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187093 91177308-0d34-0410-b5e6-96231b3b80d8
Prior to this patch, IfConverter may widen the cases where a sequence of
instructions were executed because of the way it uses nested predicates. This
result in incorrect execution.
For instance, Let A be a basic block that flows conditionally into B and B be a
predicated block.
B can be predicated with A.BrToBPredicate into A iff B.Predicate is less
"permissive" than A.BrToBPredicate, i.e., iff A.BrToBPredicate subsumes
B.Predicate.
The IfConverter was checking the opposite: B.Predicate subsumes
A.BrToBPredicate.
<rdar://problem/14379453>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187071 91177308-0d34-0410-b5e6-96231b3b80d8
The change r187019 has fixed multiple relocations in dynamic linker for
MIPS, so now this test passes for MIPS.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187053 91177308-0d34-0410-b5e6-96231b3b80d8
Improve the Finder to handle context of a DIVariable used by DbgValueInst.
Fix testing cases to make them pass the verifier.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187052 91177308-0d34-0410-b5e6-96231b3b80d8
schedule an alloca for another iteration in SROA. This only showed up
with a mixture of promotable and unpromotable selects and phis. Added
a test case for this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187031 91177308-0d34-0410-b5e6-96231b3b80d8
pending speculation for a phi node. The problem here is that we were
using growth of the specluation set as an indicator of whether
speculation would occur, and if the phi node is already in the set we
don't see it grow. This is a symptom of the fact that this signal is
a total hack.
Unfortunately, I couldn't really come up with a non-hacky way of
signaling that promotion remains valid *after* speculation occurs, such
that we only speculate when all else looks good for promotion. In the
end, I went with at least a much more explicit approach of doing the
work of queuing inside the phi and select processing and setting
a preposterously named flag to convey that we're in the special state of
requiring speculating before promotion.
Thanks to Richard Trieu and Nick Lewycky for the excellent work reducing
a testcase for this from a pretty giant, nasty assert in a big
application. =] The testcase was excellent.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187029 91177308-0d34-0410-b5e6-96231b3b80d8
This commit also implements these functions for R600 and removes a test
case that was relying on the buggy behavior.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187007 91177308-0d34-0410-b5e6-96231b3b80d8
These are really the same address space in hardware. The only
difference is that CONSTANT_ADDRESS uses a special cache for faster
access. When we are unable to use the constant kcache for some reason
(e.g. smaller types or lack of indirect addressing) then the instruction
selector must use GLOBAL_ADDRESS loads instead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187006 91177308-0d34-0410-b5e6-96231b3b80d8
Improve the Finder to handle context of a DIVariable.
If Scope is a DICompileUnit, add it to the list of CUs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187003 91177308-0d34-0410-b5e6-96231b3b80d8
When vectors are built from a single value, the ARM lowering issues a
scalar_to_vector node.
This node is then always morphed into a move from the general purpose unit to
the vector unit.
When the value comes from a load, this can be simplified into a vector load to
the right lane.
This patch changes the lowering of insert_vector_elt to expose a vector
friendly pattern in this situation.
This is a step toward fixing <rdar://problem/14170854>.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186999 91177308-0d34-0410-b5e6-96231b3b80d8
The symbol table has forward references in the file. Instead of allocating
a temporary buffer or counting the size and then writing, this implementation
writes a dummy value first and patches it once the final value is known.
There is room for performance improvement. I will implement them as soon as I
get some other features (like a ranlib mode) in.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186934 91177308-0d34-0410-b5e6-96231b3b80d8
This increases the number of opportunites we have for folding. With the
previous implementation we were unable to fold into any instructions
other than the first when multiple instructions were selected from a
single SDNode.
Reviewed-by: Vincent Lejeune <vljn at ovi.com>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186919 91177308-0d34-0410-b5e6-96231b3b80d8
A side-effect of this is that now the compiler expects kernel arguments
to be 4-byte aligned.
Reviewed-by: Vincent Lejeune <vljn at ovi.com>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186916 91177308-0d34-0410-b5e6-96231b3b80d8
MDNodes used by DbgDeclareInst and DbgValueInst.
Another 16 testing cases failed and they are disabled with
-disable-debug-info-verifier.
A total of 34 cases are disabled with -disable-debug-info-verifier and will be
corrected.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186902 91177308-0d34-0410-b5e6-96231b3b80d8
Use the function attributes to pass along the stack protector buffer size.
Now that we have robust function attributes, don't use a command line option to
specify the stack protecto buffer size.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186863 91177308-0d34-0410-b5e6-96231b3b80d8
Enable parsing all 32 floating point control registers $0-31 and stop trying to
parse floating point condition code register $fcc0. Also, return ParseFail if
the operand being parsed is not in the expected format.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186861 91177308-0d34-0410-b5e6-96231b3b80d8