1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-10-30 07:22:55 +01:00
llvm-mirror/lib/Target/PowerPC/README.txt
Chris Lattner 5ad0216bd6 add a optimization note
llvm-svn: 22732
2005-08-09 22:30:57 +00:00

37 lines
1.2 KiB
Plaintext

TODO:
* gpr0 allocation
* implement do-loop -> bdnz transform
* implement powerpc-64 for darwin
* use stfiwx in float->int
* be able to combine sequences like the following into 2 instructions:
lis r2, ha16(l2__ZTV4Cell)
la r2, lo16(l2__ZTV4Cell)(r2)
addi r2, r2, 8
* Support 'update' load/store instructions. These are cracked on the G5, but
are still a codesize win.
* Add a custom legalizer for the GlobalAddress node, to move the funky darwin
stub stuff from the instruction selector to the legalizer (exposing low-level
operations to the dag for optzn. For example, we want to codegen this:
int A = 0;
void B() { A++; }
as:
lis r9,ha16(_A)
lwz r2,lo16(_A)(r9)
addi r2,r2,1
stw r2,lo16(_A)(r9)
not:
lis r2, ha16(_A)
lwz r2, lo16(_A)(r2)
addi r2, r2, 1
lis r3, ha16(_A)
stw r2, lo16(_A)(r3)
* should hint to the branch select pass that it doesn't need to print the
second unconditional branch, so we don't end up with things like:
b .LBBl42__2E_expand_function_8_674 ; loopentry.24
b .LBBl42__2E_expand_function_8_42 ; NewDefault
b .LBBl42__2E_expand_function_8_42 ; NewDefault