This reverts commit ca907bfb57.
According to michel.daenzer,
> This completely broke the Mesa radeonsi driver on Navi 14. Xorg +
> xterm come up with major corruption & psychedelic colours.
When memory operations are outstanding on function calls, either the
caller or the callee can insert a waitcnt to ensure that all reads are
finished.
Calls need some time to be executed, so if the callee inserts the
waitcnt, filling the instruction buffer and waiting for memory will be
interleaved, hiding some latency. This comes at the cost of having a
waitcnt inside functions that may not be needed as no memory operations
are outstanding.
For function calls, this is already implemented. The same principal
applies to returns: If the caller inserts a waitcnt after the call, the
callee does not have to wait and the return and memory operation can be
run in parallel.
This commit implements waiting in the caller after returning from a
function call.
Differential Revision: https://reviews.llvm.org/D87674
Summary:
This commit adds new intrinsics
llvm.amdgcn.raw.buffer.load
llvm.amdgcn.raw.buffer.load.format
llvm.amdgcn.raw.buffer.load.format.d16
llvm.amdgcn.struct.buffer.load
llvm.amdgcn.struct.buffer.load.format
llvm.amdgcn.struct.buffer.load.format.d16
llvm.amdgcn.raw.buffer.store
llvm.amdgcn.raw.buffer.store.format
llvm.amdgcn.raw.buffer.store.format.d16
llvm.amdgcn.struct.buffer.store
llvm.amdgcn.struct.buffer.store.format
llvm.amdgcn.struct.buffer.store.format.d16
llvm.amdgcn.raw.buffer.atomic.*
llvm.amdgcn.struct.buffer.atomic.*
with the following changes from the llvm.amdgcn.buffer.*
intrinsics:
* there are separate raw and struct versions: raw does not have an
index arg and sets idxen=0 in the instruction, and struct always sets
idxen=1 in the instruction even if the index is 0, to allow for the
fact that gfx9 does bounds checking differently depending on whether
idxen is set;
* there is a combined cachepolicy arg (glc+slc)
* there are now only two offset args: one for the offset that is
included in bounds checking and swizzling, to be split between the
instruction's voffset and immoffset fields, and one for the offset
that is excluded from bounds checking and swizzling, to go into the
instruction's soffset field.
The AMDISD::BUFFER_* SD nodes always have an index operand, all three
offset operands, combined cachepolicy operand, and an extra idxen
operand.
The obsolescent llvm.amdgcn.buffer.* intrinsics continue to work.
Subscribers: arsenm, kzhuravl, wdng, nhaehnle, yaxunl, dstuttard, t-tye, jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D50306
Change-Id: If897ea7dc34fcbf4d5496e98cc99a934f62fc205
llvm-svn: 340269
Mircea Trofin