Tage

[ABenC377]

Adding a TAGE branch predictor.

Performance relative to previous best (Perceptron) summarised below:

Benchmark	BP_update time	BP_update mispredict	TAGE time	TAGE mispredict	Performance change (percentage)	Mispredict change (raw)
CloverLeaf serial gcc8.3.0 armv8.4	11715	10.70%	10511	2.06%	-10.28% ✅	-8.64% ✅
CloverLeaf serial gcc9.3.0 armv8.4	11830	10.40%	10321	1.85%	-12.76% ✅	-8.55% ✅
CloverLeaf serial gcc10.3.0 armv8.4	12457	12.70%	10550	1.74%	-15.31% ✅	-10.96% ✅
CloverLeaf serial armclang20 armv8.4	11041	14.50%	9069	1.85%	-17.86% ✅	-12.65% ✅
CloverLeaf openmp gcc8.3.0 armv8.4	15635	9.78%	14530	2.00%	-7.07% ✅	-7.78% ✅
CloverLeaf openmp gcc9.3.0 armv8.4	15559	7.82%	14680	1.64%	-5.65% ✅	-6.18% ✅
CloverLeaf openmp gcc10.3.0 armv8.4	15291	9.33%	13872	1.56%	-9.28% ✅	-7.77% ✅
CloverLeaf openmp armclang20 armv8.4	13939	13.30%	12273	1.74%	-11.95% ✅	-11.56% ✅
miniBUDE openmp gcc8.3.0 armv8.4	21292	7.37%	20613	5.71%	-3.19% ✅	-1.66% ✅
miniBUDE openmp gcc9.3.0 armv8.4	20652	7.43%	20364	5.71%	-1.39% ✅	-1.72% ✅
miniBUDE openmp gcc10.3.0 armv8.4	20810	7.41%	20691	5.71%	-0.57% ✅	-1.70% ✅
miniBUDE openmp armclang20 armv8.4	19365	10.30%	19808	5.05%	+2.29% ❌	-5.25% ✅
STREAM serial gcc8.3.0 armv8.4	6619	0.51%	6672	0.42%	+0.80% ❌	-0.09% ✅
STREAM serial gcc9.3.0 armv8.4	6612	0.50%	6778	0.42%	+2.51% ❌	-0.08% ✅
STREAM serial gcc10.3.0 armv8.4	6583	0.44%	6649	0.42%	+1.00% ❌	-0.03% ✅
STREAM serial armclang20 armv8.4	7018	1.01%	7071	0.75%	+0.76% ❌	-0.26% ✅
STREAM openmp gcc8.3.0 armv8.4	10200	1.90%	10066	0.67%	-1.31% ✅	-1.23% ✅
STREAM openmp gcc9.3.0 armv8.4	10037	2.08%	9859	0.50%	-1.77% ✅	-1.58% ✅
STREAM openmp gcc10.3.0 armv8.4	9814	1.81%	9799	0.63%	-0.15% ✅	-1.18% ✅
STREAM openmp armclang20 armv8.4	10292	3.04%	10459	1.21%	+1.62% ❌	-1.83% ✅
TeaLeaf 2D serial gcc8.3.0 armv8.4	11874	15.20%	10871	1.04%	-8.45% ✅	-14.16% ✅
TeaLeaf 2D serial gcc9.3.0 armv8.4	11846	15.20%	10847	1.05%	-8.43% ✅	-14.15% ✅
TeaLeaf 2D serial gcc10.3.0 armv8.4	12020	15.20%	11078	1.05%	-7.84% ✅	-14.15% ✅
TeaLeaf 2D serial armclang20 armv8.4	21353	9.16%	20597	3.27%	-3.54% ✅	-5.89% ✅
TeaLeaf 2D openmp gcc8.3.0 armv8.4	17221	7.05%	16118	1.18%	-6.40% ✅	-5.87% ✅
TeaLeaf 2D openmp gcc9.3.0 armv8.4	17224	7.75%	16485	1.43%	-4.29% ✅	-6.32% ✅
TeaLeaf 2D openmp gcc10.3.0 armv8.4	16595	6.70%	16221	0.85%	-2.25% ✅	-5.85% ✅
TeaLeaf 2D openmp armclang20 armv8.4	52356	9.29%	50683	2.38%	-3.20% ✅	-6.91% ✅
TeaLeaf 3D serial gcc8.3.0 armv8.4	13645	8.73%	13203	1.15%	-3.24% ✅	-7.58% ✅
TeaLeaf 3D serial gcc9.3.0 armv8.4	14157	10.70%	13463	1.57%	-4.90% ✅	-9.13% ✅
TeaLeaf 3D serial gcc10.3.0 armv8.4	14331	11.00%	13167	1.50%	-8.12% ✅	-9.50% ✅
TeaLeaf 3D serial armclang20 armv8.4	19199	22.40%	16675	1.69%	-13.15% ✅	-20.71% ✅
TeaLeaf 3D openmp gcc8.3.0 armv8.4	22251	7.62%	21775	2.30%	-2.14% ✅	-5.32% ✅
TeaLeaf 3D openmp gcc9.3.0 armv8.4	22774	9.03%	21750	1.47%	-4.50% ✅	-7.56% ✅
TeaLeaf 3D openmp gcc10.3.0 armv8.4	22229	8.33%	20867	0.99%	-6.13% ✅	-7.34% ✅
TeaLeaf 3D openmp armclang20 armv8.4	40910	16.90%	37148	1.30%	-9.20% ✅	-15.60% ✅
CloverLeaf serial gcc8.3.0 armv8.4+sve	11137	10.90%	9820	2.31%	-11.83% ✅	-8.59% ✅
CloverLeaf serial gcc9.3.0 armv8.4+sve	11051	9.98%	9909	1.86%	-10.33% ✅	-8.12% ✅
CloverLeaf serial gcc10.3.0 armv8.4+sve	11140	12.80%	9462	1.80%	-15.06% ✅	-11.00% ✅
CloverLeaf serial armclang20 armv8.4+sve	11051	13.30%	9280	1.50%	-16.03% ✅	-11.80% ✅
CloverLeaf openmp gcc8.3.0 armv8.4+sve	14845	9.65%	13076	1.87%	-11.92% ✅	-7.78% ✅
CloverLeaf openmp gcc9.3.0 armv8.4+sve	15310	7.96%	13208	1.80%	-13.73% ✅	-6.16% ✅
CloverLeaf openmp gcc10.3.0 armv8.4+sve	14754	9.62%	13397	1.56%	-9.20% ✅	-8.06% ✅
CloverLeaf openmp armclang20 armv8.4+sve	14309	12.20%	12493	1.29%	-12.69% ✅	-10.91% ✅
miniBUDE openmp gcc8.3.0 armv8.4+sve	8707	14.20%	7917	3.61%	-9.07% ✅	-10.59% ✅
miniBUDE openmp gcc9.3.0 armv8.4+sve	8440	7.43%	7656	3.54%	-9.29% ✅	-3.89% ✅
miniBUDE openmp gcc10.3.0 armv8.4+sve	8458	7.41%	7695	3.41%	-9.02% ✅	-4.00% ✅
miniBUDE openmp armclang20 armv8.4+sve	8655	20.30%	7961	1.21%	-8.02% ✅	-19.09% ✅
STREAM serial gcc8.3.0 armv8.4+sve	3521	1.51%	3572	1.28%	+1.45% ❌	-0.23% ✅
STREAM serial gcc9.3.0 armv8.4+sve	3534	1.50%	3980	1.28%	+12.62% ❌	-0.22% ✅
STREAM serial gcc10.3.0 armv8.4+sve	3481	1.44%	3787	1.28%	+8.79% ❌	-0.16% ✅
STREAM serial armclang20 armv8.4+sve	2207	2.01%	2268	1.46%	+2.76% ❌	-0.55% ✅
STREAM openmp gcc8.3.0 armv8.4+sve	6821	3.90%	6740	1.79%	-1.19% ✅	-2.11% ✅
STREAM openmp gcc9.3.0 armv8.4+sve	7198	3.08%	6686	1.01%	-7.11% ✅	-2.07% ✅
STREAM openmp gcc10.3.0 armv8.4+sve	7067	2.81%	6646	1.18%	-5.96% ✅	-1.63% ✅
STREAM openmp armclang20 armv8.4+sve	6428	3.04%	5867	1.44%	-8.73% ✅	-1.60% ✅
TeaLeaf 2D serial gcc8.3.0 armv8.4+sve	11725	15.20%	10942	1.04%	-6.68% ✅	-14.16% ✅
TeaLeaf 2D serial gcc9.3.0 armv8.4+sve	11584	15.20%	10899	1.04%	-5.91% ✅	-14.16% ✅
TeaLeaf 2D serial gcc10.3.0 armv8.4+sve	11879	15.20%	11034	1.05%	-7.11% ✅	-14.15% ✅
TeaLeaf 2D serial armclang20 armv8.4+sve	11137	9.16%	7370	0.87%	-33.82% ✅	-8.29% ✅
TeaLeaf 2D openmp gcc8.3.0 armv8.4+sve	17041	7.05%	16349	1.18%	-4.06% ✅	-5.87% ✅
TeaLeaf 2D openmp gcc9.3.0 armv8.4+sve	17451	7.75%	16532	1.43%	-5.27% ✅	-6.32% ✅
TeaLeaf 2D openmp gcc10.3.0 armv8.4+sve	16463	6.70%	16187	0.85%	-1.68% ✅	-5.85% ✅
TeaLeaf 2D openmp armclang20 armv8.4+sve	52701	9.29%	49203	1.63%	-6.64% ✅	-7.66% ✅
TeaLeaf 3D serial gcc8.3.0 armv8.4+sve	12169	18.73%	10629	1.60%	-12.66% ✅	-17.13% ✅
TeaLeaf 3D serial gcc9.3.0 armv8.4+sve	12183	18.70%	10639	1.07%	-12.67% ✅	-17.63% ✅
TeaLeaf 3D serial gcc10.3.0 armv8.4+sve	12405	18.30%	10616	1.58%	-14.42% ✅	-16.72% ✅
TeaLeaf 3D serial armclang20 armv8.4+sve	19363	22.40%	15654	1.42%	-19.16% ✅	-20.98% ✅
TeaLeaf 3D openmp gcc8.3.0 armv8.4+sve	21676	7.62%	18948	2.22%	-12.59% ✅	-5.40% ✅
TeaLeaf 3D openmp gcc9.3.0 armv8.4+sve	20728	9.03%	18989	1.51%	-8.39% ✅	-7.52% ✅
TeaLeaf 3D openmp gcc10.3.0 armv8.4+sve	20438	8.33%	18652	0.85%	-8.74% ✅	-7.48% ✅
TeaLeaf 3D openmp armclang20 armv8.4+sve	41040	8.49%	37791	0.88%	-7.92% ✅	-7.61% ✅

[JosephMoore25]

Looks all good to me. Clean implementation. Would maybe change a couple of data structures (namely branch history to a circular buffer) just to optimise memory usage, but not worth halting this PR further for. Nice work!

[dANW34V3R]

Very clean. Couple of minor comments but happy to approve

[jj16791]

All looks good, great work Alex! Looks like this cango in after it passes all the GH checks