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Performance improvements [2] #4

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Merged
maximmenshikov merged 3 commits into from
May 29, 2026
Merged

Performance improvements [2] #4

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1fc2fb8
Inline barriers
maximmenshikov May 29, 2026
e82831e
Update patch to dotnet 10
maximmenshikov May 29, 2026
1af404a
RiscV64 write barriers: drop config toggle, always inline
maximmenshikov May 29, 2026
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51 changes: 51 additions & 0 deletions patches/bflat-runtime/24_inline_write_barrier_riscv64.patch
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Original file line number Diff line number Diff line change
@@ -0,0 +1,51 @@
--- a/src/coreclr/jit/codegenriscv64.cpp
+++ b/src/coreclr/jit/codegenriscv64.cpp
@@ -2527,8 +2527,15 @@
}
else
{
- // In the case of a GC-Pointer we'll call the ByRef write barrier helper
- genEmitHelperCall(CORINFO_HELP_ASSIGN_BYREF, 0, EA_PTRSIZE);
+ // zkVM: the ByRef barrier helper is reduced to a bare
+ // *dst++ = *src++ (uGC has no card table). Inline it to drop the
+ // per-slot call/ret. Mirrors __wrap_RhpByRefAssignRef.
+ emit->emitIns_R_R_I(INS_ld, EA_8BYTE, tmpReg, REG_WRITE_BARRIER_SRC_BYREF, 0);
+ emit->emitIns_R_R_I(INS_addi, EA_PTRSIZE, REG_WRITE_BARRIER_SRC_BYREF,
+ REG_WRITE_BARRIER_SRC_BYREF, TARGET_POINTER_SIZE);
+ emit->emitIns_R_R_I(INS_sd, EA_8BYTE, tmpReg, REG_WRITE_BARRIER_DST_BYREF, 0);
+ emit->emitIns_R_R_I(INS_addi, EA_PTRSIZE, REG_WRITE_BARRIER_DST_BYREF,
+ REG_WRITE_BARRIER_DST_BYREF, TARGET_POINTER_SIZE);
gcPtrCount--;
}
++i;
@@ -3040,6 +3047,12 @@
GenTree* addr = tree->Addr();

GCInfo::WriteBarrierForm writeBarrierForm = gcInfo.gcIsWriteBarrierCandidate(tree);
+
+ // zkVM: uGC never relocates or collects and the RhpAssignRef* helpers are
+ // already reduced to a bare store, so a GC ref store is just a plain store.
+ // Force the inline-store path below (no t3/t4 marshalling, no call/ret).
+ writeBarrierForm = GCInfo::WBF_NoBarrier;
+
if (writeBarrierForm != GCInfo::WBF_NoBarrier)
{
// data and addr must be in registers.
--- a/src/coreclr/jit/lsrariscv64.cpp
+++ b/src/coreclr/jit/lsrariscv64.cpp
@@ -552,12 +552,9 @@
{
assert(dstCount == 0);

- if (compiler->codeGen->gcInfo.gcIsWriteBarrierStoreIndNode(tree->AsStoreInd()))
- {
- srcCount = BuildGCWriteBarrier(tree);
- break;
- }
-
+ // zkVM: ref stores are inlined (see genCodeForStoreInd), so never
+ // take the write-barrier path - always build an ordinary indir so
+ // the operands are not pinned to t3/t4.
srcCount = BuildIndir(tree->AsIndir());
if (!tree->gtGetOp2()->isContained())
{
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