Merge pull request #4552 from martin-frbg/issue4551

Allow negative INC_X in arm64 ThunderX2T99 and Apple M ?NRM2

Author: martin-frbg

kernel/arm64/dznrm2_thunderx2t99.c

@@ -345,7 +345,7 @@ FLOAT CNAME(BLASLONG n, FLOAT *x, BLASLONG inc_x)
 #endif
 	FLOAT ssq, scale;
 
-	if (n <= 0 || inc_x <= 0) return 0.0;
+	if (n <= 0 || inc_x == 0) return 0.0;
 
 #if defined(SMP)
 	if (n <= 10000)

kernel/arm64/scnrm2_thunderx2t99.c

@@ -315,7 +315,7 @@ FLOAT CNAME(BLASLONG n, FLOAT *x, BLASLONG inc_x)
 	FLOAT nrm2 = 0.0;
 	double nrm2_double = 0.0;
 
-	if (n <= 0 || inc_x <= 0) return 0.0;
+	if (n <= 0 || inc_x == 0) return 0.0;
 
 #if defined(SMP)
 	if (n <= 10000)