diff options
Diffstat (limited to 'llvm/lib/Target/WebAssembly/README.txt')
| -rw-r--r-- | llvm/lib/Target/WebAssembly/README.txt | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/llvm/lib/Target/WebAssembly/README.txt b/llvm/lib/Target/WebAssembly/README.txt index 4a0fa0badfb..486b587fb74 100644 --- a/llvm/lib/Target/WebAssembly/README.txt +++ b/llvm/lib/Target/WebAssembly/README.txt @@ -24,13 +24,13 @@ test suite. The tests can be run locally using: //===---------------------------------------------------------------------===// -Br, br_if, and br_table instructions can support having a value on the -expression stack across the jump (sometimes). We should (a) model this, and -(b) extend the stackifier to utilize it. +Br, br_if, and br_table instructions can support having a value on the value +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 +The min/max instructions 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. @@ -44,7 +44,7 @@ us too? //===---------------------------------------------------------------------===// -Register stackification uses the EXPR_STACK physical register to impose +Register stackification uses the VALUE_STACK physical register to impose ordering dependencies on instructions with stack operands. This is pessimistic; we should consider alternate ways to model stack dependencies. @@ -129,3 +129,11 @@ enableMachineScheduler) and determine if it can be configured to schedule instructions advantageously for this purpose. //===---------------------------------------------------------------------===// + +WebAssembly is now officially a stack machine, rather than an AST, and this +comes with additional opportunities for WebAssemblyRegStackify. Specifically, +the stack doesn't need to be empty after an instruction with no return values. +WebAssemblyRegStackify could be extended, or possibly rewritten, to take +advantage of the new opportunities. + +//===---------------------------------------------------------------------===// |
