Make autocorrelation calculation easier to vectorize

1 files changed, 36 insertions, 19 deletions

diff --git a/src/libFLAC/lpc.c b/src/libFLAC/lpc.c
index a090a877..1814fef5 100644
--- a/src/libFLAC/lpc.c
+++ b/src/libFLAC/lpc.c
@@ -130,29 +130,46 @@ void FLAC__lpc_compute_autocorrelation(const FLAC__real data[], uint32_t data_le
 		autoc[lag] = d;
 	}
 #endif
+	if(lag <= 8) {
+		#undef MAX_LAG
+		#define MAX_LAG 8
+		#include "deduplication/lpc_compute_autocorrelation_intrin.c"
+	}
+	else if(lag <= 12) {
+		#undef MAX_LAG
+		#define MAX_LAG 12
+		#include "deduplication/lpc_compute_autocorrelation_intrin.c"
+	}
+	else if(lag <= 16) {
+		#undef MAX_LAG
+		#define MAX_LAG 16
+		#include "deduplication/lpc_compute_autocorrelation_intrin.c"
+	}
+	else {
 
-	/*
-	 * this version tends to run faster because of better data locality
-	 * ('data_len' is usually much larger than 'lag')
-	 */
-	double d;
-	uint32_t sample, coeff;
-	const uint32_t limit = data_len - lag;
+		/*
+		 * this version tends to run faster because of better data locality
+		 * ('data_len' is usually much larger than 'lag')
+		 */
+		double d;
+		uint32_t sample, coeff;
+		const uint32_t limit = data_len - lag;
 
-	FLAC__ASSERT(lag > 0);
-	FLAC__ASSERT(lag <= data_len);
+		FLAC__ASSERT(lag > 0);
+		FLAC__ASSERT(lag <= data_len);
 
-	for(coeff = 0; coeff < lag; coeff++)
-		autoc[coeff] = 0.0;
-	for(sample = 0; sample <= limit; sample++) {
-		d = data[sample];
 		for(coeff = 0; coeff < lag; coeff++)
-			autoc[coeff] += d * data[sample+coeff];
-	}
-	for(; sample < data_len; sample++) {
-		d = data[sample];
-		for(coeff = 0; coeff < data_len - sample; coeff++)
-			autoc[coeff] += d * data[sample+coeff];
+			autoc[coeff] = 0.0;
+		for(sample = 0; sample <= limit; sample++) {
+			d = data[sample];
+			for(coeff = 0; coeff < lag; coeff++)
+				autoc[coeff] += d * data[sample+coeff];
+		}
+		for(; sample < data_len; sample++) {
+			d = data[sample];
+			for(coeff = 0; coeff < data_len - sample; coeff++)
+				autoc[coeff] += d * data[sample+coeff];
+		}
 	}
 }