This patch adjusts the instruction scheduling and cost model for the Zbc
(CLMUL) extension on the Spacemit X60 core.
The tuning was evaluated using three configurations (CLMUL2, CLMUL3,
and the baseline CLMUL5) across a variety of hashing and encryption kernels.
| Test Case | Met | CLMUL2 | CLMUL3 | v5 (Patch) | v5/v2 | v5/v3 |
|--------------|-----|-------------|-------------|-------------|-------|-------|
| AES Hash | ms | 1,676.94| 1,614.35| 1,614.71| -3.71%| +0.02%|
| [5bsv8qnh1] | cyc |2,683,008,256|2,582,866,539|2,583,483,082| -3.71%| +0.02%|
|--------------|-----|-------------|-------------|-------------|-------|-------|
| Sweet Spot | ms | 2,631.45| 2,631.35| 2,743.37| +4.25%| +4.26%|
| [xe9sncK87] | cyc |4,210,294,394|4,210,083,291|4,389,331,992| +4.25%| +4.26%|
|--------------|-----|-------------|-------------|-------------|-------|-------|
| 128b Mult | ms | 1,639.32| 1,727.10| 1,754.90| +7.05%| +1.61%|
| [aYezqcx4n] | cyc |2,622,877,789|2,763,259,605|2,807,789,209| +7.05%| +1.61%|
|--------------|-----|-------------|-------------|-------------|-------|-------|
| CRC32 Fold | ms | 2,056.78| 1,947.46| 2,120.03| +3.07%| +8.86%|
| [bdWoW9ezv] | cyc |3,290,804,189|3,115,896,432|3,391,980,303| +3.07%| +8.86%|
|--------------|-----|-------------|-------------|-------------|-------|-------|
| Wegman Hash | ms | 2,160.13| 2,161.12| 2,204.77| +2.07%| +2.02%|
| [aa8aGerbe] | cyc |3,456,154,927|3,457,644,543|3,527,588,691| +2.07%| +2.02%|
|--------------|-----|-------------|-------------|-------------|-------|-------|
Links:
[5bsv8qnh1] https://godbolt.org/z/5bsv8qnh1
[xe9sncK87] https://godbolt.org/z/xe9sncK87
[aYezqcx4n] https://godbolt.org/z/aYezqcx4n
[bdWoW9ezv] https://godbolt.org/z/bdWoW9ezv
[aa8aGerbe] https://godbolt.org/z/aa8aGerbe
Based on the benchmark results, CLMUL3 is proposed as the new default
tuning for this core.
2025-12-23 Milan Tripkovic <[email protected]>
gcc/ChangeLog:
* config/riscv/spacemit-x60.md (spacemit_x60_clmul): clmul value changed
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---
gcc/config/riscv/spacemit-x60.md | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/config/riscv/spacemit-x60.md b/gcc/config/riscv/spacemit-x60.md
index c991f89e5e2..b4a5352ea57 100644
--- a/gcc/config/riscv/spacemit-x60.md
+++ b/gcc/config/riscv/spacemit-x60.md
@@ -93,7 +93,7 @@
(eq_attr "mode" "DI")))
"spacemit_x60_alu")
-(define_insn_reservation "spacemit_x60_clmul" 5
+(define_insn_reservation "spacemit_x60_clmul" 3
(and (eq_attr "tune" "spacemit_x60")
(eq_attr "type" "clmul"))
"spacemit_x60_alu")
--
2.43.0
