On 5/25/23 06:35, Manolis Tsamis wrote:
This pass tries to optimize memory offset calculations by moving them
from add immediate instructions to the memory loads/stores.
For example it can transform this:
addi t4,sp,16
add t2,a6,t4
shl t3,t2,1
ld a2,0(t3)
addi a2,1
sd a2,8(t2)
into the following (one instruction less):
add t2,a6,sp
shl t3,t2,1
ld a2,32(t3)
addi a2,1
sd a2,24(t2)
Although there are places where this is done already, this pass is more
powerful and can handle the more difficult cases that are currently not
optimized. Also, it runs late enough and can optimize away unnecessary
stack pointer calculations.
The first patch in the series contains the implementation of this pass
while the second is a minor change that enables cprop_hardreg's
propgation of the stack pointer, because this pass depends on cprop
to do the propagation of optimized operations. If preferred I can split
this into two different patches (in which cases some of the testcases
included will fail temporarily).
Thanks Manolis. Do you happen to know if this includes the fixes I
passed along to Philipp a few months back? My recollection is one fixed
stale DF data which prevented an ICE during bootstrapping, the other
needed to ignore debug insns in one or two places so that the behavior
didn't change based on the existence of debug insns.
Jeff
