keep track of a sense of "mobility", i.e. how many other nodes scheduling one
node will free up. For something like this:
float testadd(float *X, float *Y, float *Z, float *W, float *V) {
return (*X+*Y)*(*Z+*W)+*V;
}
For example, this makes us schedule *X then *Y, not *X then *Z. The former
allows us to issue the add, the later only lets us issue other loads.
This turns the above code from this:
_testadd:
lfs f0, 0(r3)
lfs f1, 0(r6)
lfs f2, 0(r4)
lfs f3, 0(r5)
fadds f0, f0, f2
fadds f1, f3, f1
lfs f2, 0(r7)
fmadds f1, f0, f1, f2
blr
into this:
_testadd:
lfs f0, 0(r6)
lfs f1, 0(r5)
fadds f0, f1, f0
lfs f1, 0(r4)
lfs f2, 0(r3)
fadds f1, f2, f1
lfs f2, 0(r7)
fmadds f1, f1, f0, f2
blr
llvm-svn: 26680
Only enable this with -use-sched-latencies, I'll enable it by default with a
clean nightly tester run tonight.
PPC is the only target that provides latency info currently.
llvm-svn: 26634
class, sever its implementation from the interface. Now we can provide new
implementations of the same interface (priority computation) without touching
the scheduler itself.
llvm-svn: 26630
function of the top-down scheduler are completely bogus currently, and
having (future) PPC specific in this file is also wrong, but this is a
small incremental step.
llvm-svn: 26552
a predecessor appearing more than once in the operand list was counted as
multiple predecessor; priority1 should be updated during scheduling;
CycleBound was updated after the node is inserted into priority queue; one
of the tie breaking condition was flipped.
- Take into consideration of two address opcodes. If a predecessor is a def&use
operand, it should have a higher priority.
- Scheduler should also favor floaters, i.e. nodes that do not have real
predecessors such as MOV32ri.
- The scheduling fixes / tweaks fixed bug 478:
.text
.align 4
.globl _f
_f:
movl 4(%esp), %eax
movl 8(%esp), %ecx
movl %eax, %edx
imull %ecx, %edx
imull %eax, %eax
imull %ecx, %ecx
addl %eax, %ecx
leal (%ecx,%edx,2), %eax
ret
It is also a slight performance win (1% - 3%) for most tests.
llvm-svn: 26470
