diff --git a/lib/Target/PowerPC/README.txt b/lib/Target/PowerPC/README.txt index be6a5711e81..057a5742e07 100644 --- a/lib/Target/PowerPC/README.txt +++ b/lib/Target/PowerPC/README.txt @@ -11,6 +11,24 @@ TODO: * 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