[all-commits] [llvm/llvm-project] 3225fc: [SVE] Deal with SVE tuple call arguments correctly...
david-arm via All-commits
all-commits at lists.llvm.org
Thu Nov 12 00:42:31 PST 2020
Branch: refs/heads/master
Home: https://github.com/llvm/llvm-project
Commit: 3225fcf11eb7741d4f0b7e891685d7133aae5c7b
https://github.com/llvm/llvm-project/commit/3225fcf11eb7741d4f0b7e891685d7133aae5c7b
Author: David Sherwood <david.sherwood at arm.com>
Date: 2020-11-12 (Thu, 12 Nov 2020)
Changed paths:
M llvm/include/llvm/CodeGen/CallingConvLower.h
M llvm/include/llvm/CodeGen/TargetCallingConv.h
M llvm/lib/CodeGen/CallingConvLower.cpp
M llvm/lib/Target/AArch64/AArch64CallingConvention.cpp
M llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
A llvm/test/CodeGen/AArch64/sve-calling-convention-mixed.ll
R llvm/test/CodeGen/AArch64/sve-calling-convention-tuples-broken.ll
Log Message:
-----------
[SVE] Deal with SVE tuple call arguments correctly when running out of registers
When passing SVE types as arguments to function calls we can run
out of hardware SVE registers. This is normally fine, since we
switch to an indirect mode where we pass a pointer to a SVE stack
object in a GPR. However, if we switch over part-way through
processing a SVE tuple then part of it will be in registers and
the other part will be on the stack.
I've fixed this by ensuring that:
1. When we don't have enough registers to allocate the whole block
we mark any remaining SVE registers temporarily as allocated.
2. We temporarily remove the InConsecutiveRegs flags from the last
tuple part argument and reinvoke the autogenerated calling
convention handler. Doing this prevents the code from entering
an infinite recursion and, in combination with 1), ensures we
switch over to the Indirect mode.
3. After allocating a GPR register for the pointer to the tuple we
then deallocate any SVE registers we marked as allocated in 1).
We also set the InConsecutiveRegs flags back how they were before.
4. I've changed the AArch64ISelLowering LowerCALL and
LowerFormalArguments functions to detect the start of a tuple,
which involves allocating a single stack object and doing the
correct numbers of legal loads and stores.
Differential Revision: https://reviews.llvm.org/D90219
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