There is a problem with the
SILoadStoreOptimizer::dmasksCanBeCombined() function that can lead to
UB.
This boolean function decides if two masks can be combined into 1. The
idea here is that the bits which are "on" in one mask, don't overlap
with the "on" bits of the other. Consider an example (10 bits for
simplicity):
Mask 1: 0101101000
Mask 2: 0000000110
Those can be combined into a single mask: 0101101110.
To check if such an operation is possible, the code takes the mask
which is greater and counts how many 0s there are, starting from the
LSB and stopping at the first 1. Then, it shifts 1u by this number and
compares it with the smaller mask. The problem is that when both masks
are 0, the counter will find 32 zeroes in the first mask and will try
to do a shift by 32 positions which leads to UB.
The fix is a simple sanity check, if the bigger mask is 0 or not.
https://reviews.llvm.org/D155051
Loads and stores can be out of order in the SILoadStoreOptimizer.
When combining MachineMemOperands of two instructions operands are
sent in the IR order into the combineKnownAdjacentMMOs. At the
moment it picks the first operand and just replaces its offset and
size. This essentially loses alignment information and may generally
result in an incorrect base pointer to be used.
Use a base pointer in memory addresses order instead and only adjust
size.
Differential Revision: https://reviews.llvm.org/D120370
This will currently accept the old number of bytes syntax, and convert
it to a scalar. This should be removed in the near future (I think I
converted all of the tests already, but likely missed a few).
Not sure what the exact syntax and policy should be. We can continue
printing the number of bytes for non-generic instructions to avoid
test churn and only allow non-scalar types for generic instructions.
This will currently print the LLT in parentheses, but accept parsing
the existing integers and implicitly converting to scalar. The
parentheses are a bit ugly, but the parser logic seems unable to deal
without either parentheses or some keyword to indicate the start of a
type.
Replace individual operands GLC, SLC, and DLC with a single cache_policy
bitmask operand. This will reduce the number of operands in MIR and I hope
the amount of code. These operands are mostly 0 anyway.
Additional advantage that parser will accept these flags in any order unlike
now.
Differential Revision: https://reviews.llvm.org/D96469
12994a70cf7 did this for 128-bit classes:
SGPR_128 only includes the real allocatable SGPRs, and SReg_128 adds
the additional non-allocatable TTMP registers. There's no point in
allocating SReg_128 vregs. This shrinks the size of the classes
regalloc needs to consider, which is usually good.
This patch extends it to all classes > 64 bits, for consistency.
Differential Revision: https://reviews.llvm.org/D78622
Summary:
Extend the SI Load/Store optimizer to merge MIMG load instructions. Handle
different flavours of image_load and image_sample instructions.
When the instructions of the same subclass differ only in dmask, merge
them and update dmask accordingly.
Reviewers: nhaehnle
Reviewed By: nhaehnle
Subscribers: arsenm, kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64911
llvm-svn: 374984
