to be really bad. Once they are joined they are not broken apart. Also, physical
intervals cannot be spilled!
Added a heuristic as a workaround for this. Be careful coalescing with a
physical register if the virtual register uses are "far". Check if there are
uses in the same loop as the source (copy instruction). Check if it is in the
loop preheader, etc.
llvm-svn: 35134
it as a late BURR scheduling tie-breaker.
Intuitively, it's good to push down instructions whose results are liveout so
their long live ranges won't conflict with other values which are needed inside
the BB. Further prioritize liveout instructions by the number of operands which
are calculated within the BB.
llvm-svn: 35109
e.g.
t1 = op t2, c1
t3 = op t4, c2
and the following instructions are both ready.
t2 = op c3
t4 = op c4
Then schedule t2 = op first.
i.e.
t4 = op c4
t2 = op c3
t1 = op t2, c1
t3 = op t4, c2
This creates more short live intervals which work better with the register
allocator.
llvm-svn: 35089
the lo-reg first. This is fallout from my ppc calling conv change yesterday,
it fixes test/ExecutionEngine/2003-05-06-LivenessClobber.llx
llvm-svn: 34983
addc, turn it into add.
This allows us to compile:
long long test(long long A, unsigned B) {
return (A + ((long long)B << 32)) & 123;
}
into:
_test:
movl $123, %eax
andl 4(%esp), %eax
xorl %edx, %edx
ret
instead of:
_test:
xorl %edx, %edx
movl %edx, %eax
addl 4(%esp), %eax ;; add of zero
andl $123, %eax
ret
llvm-svn: 34909
entry (0x8b056f0, LLVM BB @0x8b01b30, ID#0):
Live Ins: %r0 %r1 %r2 %r3
%reg1032 = tMOVrr %r3<kill>
%reg1033 = tMOVri8 1
%reg1034 = tMOVri8 0
tCMPi8 %reg1029<kill>, 0
tBcc mbb<entry,0x8b06a10>, 0
Successors according to CFG: 0x8b06980 0x8b06a10
entry (0x8b06980, LLVM BB @0x8b01b30, ID#12):
Predecessors according to CFG: 0x8b056f0
%reg1036 = tMOVrr %reg1034<kill>
Successors according to CFG: 0x8b06a10
entry (0x8b06a10, LLVM BB @0x8b01b30, ID#13):
Predecessors according to CFG: 0x8b056f0 0x8b06980
%reg1024<dead> = tMOVrr %reg1030<kill>
...
reg1030 and r1 have already been joined. When reg1024 and reg1030 are joined,
r1 live range from function entry to the tMOVrr instruction are dead. Eliminate
r1 from the livein set of the entry BB, not the BB where the copy is.
llvm-svn: 34866
