diff options
Diffstat (limited to 'include/llvm/MC/MCSchedule.h')
| -rw-r--r-- | include/llvm/MC/MCSchedule.h | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/include/llvm/MC/MCSchedule.h b/include/llvm/MC/MCSchedule.h index 6881e1d..d1ab411 100644 --- a/include/llvm/MC/MCSchedule.h +++ b/include/llvm/MC/MCSchedule.h @@ -32,11 +32,16 @@ struct MCProcResourceDesc { // Number of resources that may be buffered. // - // Buffered resources (BufferSize > 0 || BufferSize == -1) may be consumed at - // some indeterminate cycle after dispatch (e.g. for instructions that may - // issue out-of-order). Unbuffered resources (BufferSize == 0) always consume - // their resource some fixed number of cycles after dispatch (e.g. for - // instruction interlocking that may stall the pipeline). + // Buffered resources (BufferSize != 0) may be consumed at some indeterminate + // cycle after dispatch. This should be used for out-of-order cpus when + // instructions that use this resource can be buffered in a reservaton + // station. + // + // Unbuffered resources (BufferSize == 0) always consume their resource some + // fixed number of cycles after dispatch. If a resource is unbuffered, then + // the scheduler will avoid scheduling instructions with conflicting resources + // in the same cycle. This is for in-order cpus, or the in-order portion of + // an out-of-order cpus. int BufferSize; bool operator==(const MCProcResourceDesc &Other) const { @@ -149,7 +154,7 @@ public: // but we balance those stalls against other heuristics. // // "> 1" means the processor is out-of-order. This is a machine independent - // estimate of highly machine specific characteristics such are the register + // estimate of highly machine specific characteristics such as the register // renaming pool and reorder buffer. unsigned MicroOpBufferSize; static const unsigned DefaultMicroOpBufferSize = 0; |