* For case bcmp9, there is extras AND and EXTEND int the chain of OR/XOR,
which prevent the transform, so enable the optimize before legalization.
* The key IR frag related:
t37: i32,ch = load<(load (s8) from %ir.4), anyext from i8> t0, t11, undef:i64
t12: i64 = add t4, Constant:i64<8>
t38: i32,ch = load<(load (s8) from %ir.5), anyext from i8> t0, t12, undef:i64
t39: i32 = xor t37, t38
t40: i64 = any_extend t39
t42: i64 = and t40, Constant:i64<255>
Depends on D138398 to fix combine_setcc_glue
Reviewed By: dmgreen, bcl5980
Differential Revision: https://reviews.llvm.org/D137936
For below case, virtual register is defined twice in the self loop. We
don't need to spill %0 after the third instruction `%0 = def (tied %0)`,
because it is defined in the second instruction `%0 = def`.
1 bb.1
2 %0 = def
3 %0 = def (tied %0)
4 ...
5 jmp bb.1
Reviewed By: MatzeB
Differential Revision: https://reviews.llvm.org/D125079
`performFlagSettingCombine` is a generalised version of `performANDSCombine` which also works on `ADCS` and `SBCS`.
Differential revision: https://reviews.llvm.org/D124464
Add a comment when there is a shifted value,
add x9, x0, #291, lsl #12 ; =1191936
but not when the immediate value is unshifted,
subs x9, x0, #256 ; =256
when the comment adds nothing additional to the reader.
Differential Revision: https://reviews.llvm.org/D107196
Basically two parts to this fix:
1. Stop using AtomicExpand to expand cmpxchg i128
2. Fix AArch64ExpandPseudoInsts to use a correct expansion.
From ARM architecture reference:
To atomically load two 64-bit quantities, perform a Load-Exclusive
pair/Store-Exclusive pair sequence of reading and writing the same value
for which the Store-Exclusive pair succeeds, and use the read values
from the Load-Exclusive pair.
Fixes https://bugs.llvm.org/show_bug.cgi?id=51102
Differential Revision: https://reviews.llvm.org/D106039
Apply the same logic used to check if CMPXCHG nodes should be expanded
at -O0: the register allocator may end up spilling some register in
between the atomic load/store pairs, breaking the atomicity and possibly
stalling the execution.
Fixes PR48017
Reviewed By: efriedman
Differential Revision: https://reviews.llvm.org/D101163
