Summary:
Avoids tons of prologue boilerplate when arguments are passed in memory
and left in memory. This can happen in a debug build or in a release
build when an argument alloca is escaped. This will dramatically affect
the code size of x86 debug builds, because X86 fast isel doesn't handle
arguments passed in memory at all. It only handles the x86_64 case of up
to 6 basic register parameters.
This is implemented by analyzing the entry block before ISel to identify
copy elision candidates. A copy elision candidate is an argument that is
used to fully initialize an alloca before any other possibly escaping
uses of that alloca. If an argument is a copy elision candidate, we set
a flag on the InputArg. If the the target generates loads from a fixed
stack object that matches the size and alignment requirements of the
alloca, the SelectionDAG builder will delete the stack object created
for the alloca and replace it with the fixed stack object. The load is
left behind to satisfy any remaining uses of the argument value. The
store is now dead and is therefore elided. The fixed stack object is
also marked as mutable, as it may now be modified by the user, and it
would be invalid to rematerialize the initial load from it.
Supersedes D28388
Fixes PR26328
Reviewers: chandlerc, MatzeB, qcolombet, inglorion, hans
Subscribers: igorb, llvm-commits
Differential Revision: https://reviews.llvm.org/D29668
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@296683 91177308-0d34-0410-b5e6-96231b3b80d8
The vectorcall calling convention specifies that arguments to functions are to be passed in registers, when possible.
vectorcall uses more registers for arguments than fastcall or the default x64 calling convention use.
The vectorcall calling convention is only supported in native code on x86 and x64 processors that include Streaming SIMD Extensions 2 (SSE2) and above.
The current implementation does not handle Homogeneous Vector Aggregates (HVAs) correctly and this review attempts to fix it.
This aubmit also includes additional lit tests to cover better HVAs corner cases.
Differential Revision: https://reviews.llvm.org/D27392
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290240 91177308-0d34-0410-b5e6-96231b3b80d8
A ``swifterror`` attribute can be applied to a function parameter or an
AllocaInst.
This commit does not include any target-specific change. The target-specific
optimization will come as a follow-up patch.
Differential Revision: http://reviews.llvm.org/D18092
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265189 91177308-0d34-0410-b5e6-96231b3b80d8
This adds support for the MCU psABI in a way different from r251223 and r251224,
basically reverting most of these two patches. The problem with the approach
taken in r251223/4 is that it only handled libcalls that originated from the backend.
However, the mid-end also inserts quite a few libcalls and assumes these use the
platform's default calling convention.
The previous patch tried to insert inregs when necessary both in the FE and,
somewhat hackily, in the CG. Instead, we now define a new default calling convention
for the MCU, which doesn't use inreg marking at all, similarly to what x86-64 does.
Differential Revision: http://reviews.llvm.org/D15054
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256494 91177308-0d34-0410-b5e6-96231b3b80d8
The patch is generated using this command:
tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
-checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
llvm/lib/
Thanks to Eugene Kosov for the original patch!
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This adds a safe interface to the machine independent InputArg struct
for accessing the index of the original (IR-level) argument. When a
non-native return type is lowered, we generate the hidden
machine-level sret argument on-the-fly. Before this fix, we were
representing this argument as OrigArgIndex == 0, which is an outright
lie. In particular this crashed in the AArch64 backend where we
actually try to access the type of the original argument.
Now we use a sentinel value for machine arguments that have no
original argument index. AArch64, ARM, Mips, and PPC now check for this
case before accessing the original argument.
Fixes <rdar://19792160> Null pointer assertion in AArch64TargetLowering
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229413 91177308-0d34-0410-b5e6-96231b3b80d8
When using the ARM AAPCS, HFAs (Homogeneous Floating-point Aggregates) must
be passed in a block of consecutive floating-point registers, or on the stack.
This means that unused floating-point registers cannot be back-filled with
part of an HFA, however this can currently happen. This patch, along with the
corresponding clang patch (http://reviews.llvm.org/D3083) prevents this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208413 91177308-0d34-0410-b5e6-96231b3b80d8
Calls with inalloca are lowered by skipping all stores for arguments
passed in memory and the initial stack adjustment to allocate argument
memory.
Now the frontend is responsible for the memory layout, and the backend
doesn't have to do any work. As a result these changes are pretty
minimal.
Reviewers: echristo
Differential Revision: http://llvm-reviews.chandlerc.com/D2637
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200596 91177308-0d34-0410-b5e6-96231b3b80d8
For some targets, it is useful to be able to look at the original
type of an argument without having to dig through the original IR.
This also fixes a bug in SelectionDAGBuilder where InputArg.PartOffset
was not taking into account the offset of structure elements.
Patch by: Justin Holewinski
Tom Stellard:
- Changed the type of ArgVT to EVT, so it can store non-simple types
like v3i32.
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InputArg in r165616.
This will enable us to get the actual type for both InputArg and OutputArg.
rdar://9932559
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SchedulerDAGInstrs::buildSchedGraph ignores dependencies between FixedStack
objects and byval parameters. So loading byval parameters from stack may be
inserted *before* it will be stored, since these operations are treated as
independent.
Fix:
Currently ARMTargetLowering::LowerFormalArguments saves byval registers with
FixedStack MachinePointerInfo. To fix the problem we need to store byval
registers with MachinePointerInfo referenced to first the "byval" parameter.
Also commit adds two new fields to the InputArg structure: Function's argument
index and InputArg's part offset in bytes relative to the start position of
Function's argument. E.g.: If function's argument is 128 bit width and it was
splitted onto 32 bit regs, then we got 4 InputArg structs with same arg index,
but different offset values.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165616 91177308-0d34-0410-b5e6-96231b3b80d8
value type, so there is no point in passing it around using
an EVT. Use the simpler MVT everywhere. Rather than trying
to propagate this information maximally in all the code that
using the calling convention stuff, I chose to do a mainly
low impact change instead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118167 91177308-0d34-0410-b5e6-96231b3b80d8
