Summary:
Multi-dword constant loads generated unnecessary moves from SGPRs into VGPRs,
increasing the code size and VGPR pressure. These moves are now folded away.
Note that this lack of operand folding was not a problem for VMEM loads,
because COPY nodes from VReg_Nnn to VGPR32 are eliminated by the register
coalescer.
Some tests are updated, note that the fsub.ll test explicitly checks that
the move is elided.
With the IR generated by current Mesa, the changes are obviously relatively
minor:
7063 shaders in 3531 tests
Totals:
SGPRS: 351872 -> 352560 (0.20 %)
VGPRS: 199984 -> 200732 (0.37 %)
Code Size: 9876968 -> 9881112 (0.04 %) bytes
LDS: 91 -> 91 (0.00 %) blocks
Scratch: 1779712 -> 1767424 (-0.69 %) bytes per wave
Wait states: 295164 -> 295337 (0.06 %)
Totals from affected shaders:
SGPRS: 65784 -> 66472 (1.05 %)
VGPRS: 38064 -> 38812 (1.97 %)
Code Size: 1993828 -> 1997972 (0.21 %) bytes
LDS: 42 -> 42 (0.00 %) blocks
Scratch: 795648 -> 783360 (-1.54 %) bytes per wave
Wait states: 54026 -> 54199 (0.32 %)
Reviewers: tstellarAMD, arsenm, mareko
Subscribers: arsenm, llvm-commits
Differential Revision: http://reviews.llvm.org/D15875
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257074 91177308-0d34-0410-b5e6-96231b3b80d8
There may be other use operands that also need their kill flags cleared.
This happens in a few tests when SIFoldOperands is moved after
PeepholeOptimizer.
PeepholeOptimizer rewrites cases that look like:
%vreg0 = ...
%vreg1 = COPY %vreg0
use %vreg1<kill>
%vreg2 = COPY %vreg0
use %vreg2<kill>
to use the earlier source to
%vreg0 = ...
use %vreg0
use %vreg0
Currently SIFoldOperands sees the copied registers, so there is
only one use. So far I haven't managed to come up with a test
that currently has multiple uses of a foldable VGPR -> VGPR copy.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@250960 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
We were assuming tha if the use operand had a sub-register that
the immediate was 64-bits, but this was breaking the case of
folding a 64-bit immediate into another 64-bit instruction.
Reviewers: arsenm
Subscribers: arsenm, llvm-commits
Differential Revision: http://reviews.llvm.org/D12255
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246354 91177308-0d34-0410-b5e6-96231b3b80d8
