mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-27 15:29:51 +00:00
45c7544339
(4.58s vs 3.2s on an oldish Mac Tower).
The corresponding src is excerpted bellow. The lopp accounts for about 90% of execution time.
--------------------
cat -n test-suite/MultiSource/Benchmarks/Olden/em3d/make_graph.c
90
91 for (k=0; k<j; k++)
92 if (other_node == cur_node->to_nodes[k]) break;
The defective layout is sketched bellow, where the two branches need to swap.
------------------------------------------------------------------------
L:
...
if (cond) goto out-of-loop
goto L
While this code sequence is defective, I don't understand why it incurs 1/3 of
execution time. CPU-event-profiling indicates the poor laoyout dose not increase
in br-misprediction; it dosen't increase stall cycle at all, and it dosen't
prevent the CPU detect the loop (i.e. Loop-Stream-Detector seems to be working fine
as well)...
The root cause of the problem is that the layout pass calls AnalyzeBranch()
with basic-block which is not updated to reflect its current layout.
rdar://13966341
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183174 91177308-0d34-0410-b5e6-96231b3b80d8
|
||
|---|---|---|
| .. | ||
| Analysis | ||
| Archive | ||
| AsmParser | ||
| Bitcode | ||
| CodeGen | ||
| DebugInfo | ||
| ExecutionEngine | ||
| IR | ||
| IRReader | ||
| Linker | ||
| MC | ||
| Object | ||
| Option | ||
| Support | ||
| TableGen | ||
| Target | ||
| Transforms | ||
| CMakeLists.txt | ||
| LLVMBuild.txt | ||
| Makefile | ||