diff options
Diffstat (limited to 'llvm/lib/Target')
| -rw-r--r-- | llvm/lib/Target/WebAssembly/README.txt | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/llvm/lib/Target/WebAssembly/README.txt b/llvm/lib/Target/WebAssembly/README.txt index 78b3123cde8..97072ab1cc1 100644 --- a/llvm/lib/Target/WebAssembly/README.txt +++ b/llvm/lib/Target/WebAssembly/README.txt @@ -47,3 +47,46 @@ expression stack across the jump (sometimes). We should (a) model this, and (b) extend the stackifier to utilize it. //===---------------------------------------------------------------------===// + +The min/max operators aren't exactly a<b?a:b because of NaN and negative zero +behavior. The ARM target has the same kind of min/max instructions and has +implemented optimizations for them; we should do similar optimizations for +WebAssembly. + +//===---------------------------------------------------------------------===// + +AArch64 runs SeparateConstOffsetFromGEPPass, followed by EarlyCSE and LICM. +Would these be useful to run for WebAssembly too? Also, it has an option to +run SimplifyCFG after running the AtomicExpand pass. Would this be useful for +us too? + +//===---------------------------------------------------------------------===// + +When is it profitable to set isAsCheapAsAMove on instructions in WebAssembly? + +//===---------------------------------------------------------------------===// + +Register stackification uses the EXPR_STACK physical register to impose +ordering dependencies on instructions with stack operands. This is pessimistic; +we should consider alternate ways to model stack dependencies. + +//===---------------------------------------------------------------------===// + +Lots of things could be done in WebAssemblyTargetTransformInfo.cpp. Similarly, +there are numerous optimization-related hooks that can be overridden in +WebAssemblyTargetLowering. + +//===---------------------------------------------------------------------===// + +Instead of the OptimizeReturned pass, which should consider preserving the +"returned" attribute through to MachineInstrs and extending the StoreResults +pass to do this optimization on calls too. That would also let the +WebAssemblyPeephole pass clean up dead defs for such calls, as it does for +stores. + +//===---------------------------------------------------------------------===// + +Memset/memcpy/memmove should be marked with the "returned" attribute somehow, +even when they are translated through intrinsics. + +//===---------------------------------------------------------------------===// |
