The LDS output queue is accessed via the OQAP register. The OQAP
register cannot be live across clauses, so if value is written to the
output queue, it must be retrieved before the end of the clause.
With the machine scheduler, we cannot statisfy this constraint, because
it lacks proper alias analysis and it will mark some LDS accesses as
having a chain dependency on vertex fetches. Since vertex fetches
require a new clauses, the dependency may end up spiltting OQAP uses and
defs so the end up in different clauses. See the lds-output-queue.ll
test for a more detailed explanation.
To work around this issue, we now combine the LDS read and the OQAP
copy into one instruction and expand it after register allocation.
This patch also adds some checks to the EmitClauseMarker pass, so that
it doesn't end a clause with a value still in the output queue and
removes AR.X and OQAP handling from the scheduler (AR.X uses and defs
were already being expanded post-RA, so the scheduler will never see
them).
Reviewed-by: Vincent Lejeune <vljn at ovi.com>
llvm-svn: 194755
The AMDGPUIndirectAddressing pass was previously responsible for
lowering private loads and stores to indirect addressing instructions.
However, this pass was buggy and way too complicated. The only
advantage it had over the new simplified code was that it saved one
instruction per direct write to private memory. This optimization
likely has a minimal impact on performance, and we may be able
to duplicate it using some other transformation.
For the private address space, we now:
1. Lower private loads/store to Register(Load|Store) instructions
2. Reserve part of the register file as 'private memory'
3. After regalloc lower the Register(Load|Store) instructions to
MOV instructions that use indirect addressing.
llvm-svn: 193179
Using REG_SEQUENCE for BUILD_VECTOR rather than a series of INSERT_SUBREG
instructions should make it easier for the register allocator to coalasce
unnecessary copies.
v2:
- Use an SGPR register class if all the operands of BUILD_VECTOR are
SGPRs.
llvm-svn: 188427
This stops the Machine Verifier from complaining about uses of undefined
physical registers.
NOTE: This is a candidate for the Mesa stable branch.
llvm-svn: 175518
Use sub0-15 everywhere.
Patch by: Michel Dänzerr
Reviewed-by: Tom Stellard <thomas.stellard@amd.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
llvm-svn: 174610
Only implemented for R600 so far. SI is missing implementations of a
few callbacks used by the Indirect Addressing pass and needs code to
handle frame indices.
At the moment R600 only supports array sizes of 16 dwords or less.
Register packing of vector types is currently disabled, which means that a
vec4 is stored in T0_X, T1_X, T2_X, T3_X, rather than T0_XYZW. In order
to correctly pack registers in all cases, we will need to implement an
analysis pass for R600 that determines the correct vector width for each
array.
v2:
- Add support for i8 zext load from stack.
- Coding style fixes
v3:
- Don't reserve registers for indirect addressing when it isn't
being used.
- Fix bug caused by LLVM limiting the number of SubRegIndex
declarations.
v4:
- Fix 64-bit defines
llvm-svn: 174525
Use one intrinsic for all sorts of interpolation.
Use two separate unexpanded instructions to represent INTERP_XY and _ZW -
this will allow to eliminate one part if it's not used.
Track liveness of special interpolation regs instead of reserving them -
this will allow to reuse those regs, lowering reg pressure.
Patch By: Vadim Girlin
v2[Vincent Lejeune]: Rebased against current llvm master
Signed-off-by: Vadim Girlin <vadimgirlin@gmail.com>
Reviewed-by: Tom Stellard <thomas.stellard@amd.com>
llvm-svn: 174394
Remove Cxxx registers, add new special register - "ALU_CONST" and new
operand for each alu src - "sel". ALU_CONST is used to designate that the
new operand contains the value to override src.sel, src.kc_bank, src.chan
for constants in the driver.
Patch by: Vadim Girlin
Vincent Lejeune:
- Use pointers for constants
- Fold CONST_ADDRESS when possible
Tom Stellard:
- Give CONSTANT_BUFFER_0 its own address space
- Use integer types for constant loads
Reviewed-by: Tom Stellard <thomas.stellard@amd.com>
llvm-svn: 173222
