Summary:
Fix case where a pre-inc/dec load/store would not be formed if the
add/sub that forms the inc/dec part of the operation was the first
instruction in the block being examined.
Reviewers: mcrosier, jmolloy, t.p.northover, junbuml
Subscribers: aemerson, rengolin, mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D16785
llvm-svn: 260275
The logic to pair instructions and merge narrow instructions has become cloogy
and error prone. This patch beings to unravel these two similar, but distinct
optimizations.
llvm-svn: 260242
This only impacts the creation of pre-/post-index instructions. The bound was
set high enough such that it did not change code generation for SPEC200X.
llvm-svn: 259828
This patch allows the mixing of scaled and unscaled load/stores to form
load/store pairs.
PR24465
http://reviews.llvm.org/D12116
Many thanks to Ahmed and Michael for fixes and code review.
This is a reapplication of r246769 and r259790. The tramp3d failure was caused
by an incorrect refactoring in the patch. Specifically, we weren't always
properly clearing the SExtIdx flag.
llvm-svn: 259812
This patch allows the mixing of scaled and unscaled load/stores to form
load/store pairs.
PR24465
http://reviews.llvm.org/D12116
Many thanks to Ahmed and Michael for fixes and code review.
This is a reapplication of r246769, which was reverted in r246782 due to a
test-suite failure. I'm unable to reproduce the issue at this time.
llvm-svn: 259790
In the discussion on http://reviews.llvm.org/D15730, Andy pointed out we had a utility function for merging MMO lists. Since it turned we actually had two copies and there's another review in progress (http://reviews.llvm.org/D15230) which needs the same, extract it into a utility function and clean up the interfaces to make it easier to use with a MachineInstBuilder.
I introduced a pair here to track size and allocation together. I think we should probably move in the direction of the MachineOperandsRef helper class, but I'm leaving that for further work. I want to get the poison state introduced before I make major changes to the interface.
Differential Revision: http://reviews.llvm.org/D15757
llvm-svn: 256909
This is a recommit of r256004 which was reverted in r256160. The issue was the
incorrect promotion for half and byte loads transformed into mov instructions.
This fix will replace half and byte type loads only with bit field extracts.
Original commit message:
This change promotes load instructions which directly read from stored by
replacing them with mov instructions. If the store is wider than the load,
the load will be replaced with a bitfield extract.
For example :
STRWui %W1, %X0, 1
%W0 = LDRHHui %X0, 3
becomes
STRWui %W1, %X0, 1
%W0 = UBFMWri %W1, 16, 31
llvm-svn: 256249
This change promotes load instructions which directly read from stores by
replacing them with mov instructions. If the store is wider than the load,
the load will be replaced with a bitfield extract.
For example :
STRWui %W1, %X0, 1
%W0 = LDRHHui %X0, 3
becomes
STRWui %W1, %X0, 1
%W0 = UBFMWri %W1, 16, 31
llvm-svn: 256004
This change merges adjacent zero stores into a wider single store.
For example :
strh wzr, [x0]
strh wzr, [x0, #2]
becomes
str wzr, [x0]
This will fix PR25410.
llvm-svn: 253711
Summary :
* Rename isSmallTypeLdMerge() to isNarrowLoad().
* Rename NumSmallTypeMerged to NumNarrowTypePromoted.
* Use Subtarget defined as a member variable.
llvm-svn: 253587
This change extends r251438 to handle more narrow load promotions
including byte type, unscaled, and signed. For example, this change will
convert :
ldursh w1, [x0, #-2]
ldurh w2, [x0, #-4]
into
ldur w2, [x0, #-4]
asr w1, w2, #16
and w2, w2, #0xffff
llvm-svn: 253577
For big-endian targets, when we merge two halfword loads into a word load, the
order of the halfwords in the loaded value is reversed compared to
little-endian, so the load-store optimiser needs to swap the destination
registers.
This does not affect merging of two word loads, as we use ldp, which treats the
memory as two separate 32-bit words.
llvm-svn: 252597
The benefit from converting narrow loads into a wider load (r251438) could be
micro-architecturally dependent, as it assumes that a single load with two bitfield
extracts is cheaper than two narrow loads. Currently, this conversion is
enabled only in cortex-a57 on which performance benefits were verified.
llvm-svn: 252316
This recommits r250719, which caused a failure in SPEC2000.gcc
because of the incorrect insert point for the new wider load.
Convert two halfword loads into a single 32-bit word load with bitfield extract
instructions. For example :
ldrh w0, [x2]
ldrh w1, [x2, #2]
becomes
ldr w0, [x2]
ubfx w1, w0, #16, #16
and w0, w0, #ffff
llvm-svn: 251438
Convert two halfword loads into a single 32-bit word load with bitfield extract
instructions. For example :
ldrh w0, [x2]
ldrh w1, [x2, #2]
becomes
ldr w0, [x2]
ubfx w1, w0, #16, #16
and w0, w0, #ffff
llvm-svn: 250719
Support for pairing unscaled loads and stores has been enabled since the
original ARM64 port. This feature is no longer experimental, AFAICT.
llvm-svn: 249049
Previously, the index was constrained to the size of the memory operation for
no apparent reason. This change removes that constraint so that we can form
pre-index instructions with any valid offset.
llvm-svn: 248931
The immediate in the load/store should be scaled by the size of the memory
operation, not the size of the register being loaded/stored. This change gets
us one step closer to forming LDPSW instructions. This change also enables
pre- and post-indexing for halfword and byte loads and stores.
llvm-svn: 248804
Chad Rosier