cpu, probe: Fix elastic trace register dependency
Change-Id: I017852eac183fac3f914fdb96d7e72a56ea9d682
Reviewed-by: Nathanael Premillieu <nathanael.premillieu@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/5121
Reviewed-by: Matthias Jung <jungma@eit.uni-kl.de>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
diff --git a/src/cpu/o3/probe/elastic_trace.cc b/src/cpu/o3/probe/elastic_trace.cc
index 08ef665..508140e 100644
--- a/src/cpu/o3/probe/elastic_trace.cc
+++ b/src/cpu/o3/probe/elastic_trace.cc
@@ -238,23 +238,31 @@
// dependency on the last writer.
int8_t max_regs = dyn_inst->numSrcRegs();
for (int src_idx = 0; src_idx < max_regs; src_idx++) {
- // Get the physical register index of the i'th source register.
- PhysRegIdPtr src_reg = dyn_inst->renamedSrcRegIdx(src_idx);
- DPRINTFR(ElasticTrace, "[sn:%lli] Check map for src reg"
- " %i (%s)\n", seq_num,
- src_reg->index(), src_reg->className());
- auto itr_last_writer = physRegDepMap.find(src_reg->flatIndex());
- if (itr_last_writer != physRegDepMap.end()) {
- InstSeqNum last_writer = itr_last_writer->second;
- // Additionally the dependency distance is kept less than the window
- // size parameter to limit the memory allocation to nodes in the
- // graph. If the window were tending to infinite we would have to
- // load a large number of node objects during replay.
- if (seq_num - last_writer < depWindowSize) {
- // Record a physical register dependency.
- exec_info_ptr->physRegDepSet.insert(last_writer);
+
+ const RegId& src_reg = dyn_inst->srcRegIdx(src_idx);
+ if (!src_reg.isMiscReg() &&
+ !src_reg.isZeroReg()) {
+ // Get the physical register index of the i'th source register.
+ PhysRegIdPtr phys_src_reg = dyn_inst->renamedSrcRegIdx(src_idx);
+ DPRINTFR(ElasticTrace, "[sn:%lli] Check map for src reg"
+ " %i (%s)\n", seq_num,
+ phys_src_reg->flatIndex(), phys_src_reg->className());
+ auto itr_writer = physRegDepMap.find(phys_src_reg->flatIndex());
+ if (itr_writer != physRegDepMap.end()) {
+ InstSeqNum last_writer = itr_writer->second;
+ // Additionally the dependency distance is kept less than the
+ // window size parameter to limit the memory allocation to
+ // nodes in the graph. If the window were tending to infinite
+ // we would have to load a large number of node objects during
+ // replay.
+ if (seq_num - last_writer < depWindowSize) {
+ // Record a physical register dependency.
+ exec_info_ptr->physRegDepSet.insert(last_writer);
+ }
}
+
}
+
}
// Loop through the destination registers of this instruction and update
@@ -270,7 +278,7 @@
// register.
PhysRegIdPtr phys_dest_reg = dyn_inst->renamedDestRegIdx(dest_idx);
DPRINTFR(ElasticTrace, "[sn:%lli] Update map for dest reg"
- " %i (%s)\n", seq_num, dest_reg.index(),
+ " %i (%s)\n", seq_num, phys_dest_reg->flatIndex(),
dest_reg.className());
physRegDepMap[phys_dest_reg->flatIndex()] = seq_num;
}
