diff options
| author | Chris Lattner <sabre@nondot.org> | 2005-08-09 22:30:57 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2005-08-09 22:30:57 +0000 |
| commit | c7e18a10d412b24fd1054851a8ad277a3a747471 (patch) | |
| tree | 3570566322785d72e49253bafde9097a415af609 /lib | |
| parent | 079a27a0deca2501485da55701632cf9ebe4e8c4 (diff) | |
add a optimization note
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22732 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Target/PowerPC/README.txt | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/lib/Target/PowerPC/README.txt b/lib/Target/PowerPC/README.txt index be6a5711e8..057a5742e0 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 |