From f8ad5344c210960fc399ca5b0ad8559ab5ca253e Mon Sep 17 00:00:00 2001
From: Bart Oldeman <bart.oldeman@calculquebec.ca>
Date: Fri, 17 Nov 2023 23:49:34 +0000
Subject: [PATCH] Fix casum fallback kernel.

This kernel is only used on Skylake+ if the kernel with AVX512
intrinsics can't be used, but used the variable x1 incorrectly
in the tail end of the loop, as it is still at the initial
value instead of where x points to.

This caused 55 "other error"s in the LAPACK tests
(https://github.com/OpenMathLib/OpenBLAS/issues/4282)

This change makes casum.c as similar as possible as zasum.c,
because zasum.c does this correctly.
---
 kernel/x86_64/casum.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/kernel/x86_64/casum.c b/kernel/x86_64/casum.c
index e4d0543114..28d78d2797 100644
--- a/kernel/x86_64/casum.c
+++ b/kernel/x86_64/casum.c
@@ -9,12 +9,12 @@
 #endif
 
 #ifndef HAVE_CASUM_KERNEL
-static FLOAT casum_kernel(BLASLONG n, FLOAT *x1)
+static FLOAT casum_kernel(BLASLONG n, FLOAT *x)
 {
 
     BLASLONG i=0;
     BLASLONG n_8 = n & -8;
-    FLOAT *x = x1;
+    FLOAT *x1 = x;
     FLOAT temp0, temp1, temp2, temp3;
     FLOAT temp4, temp5, temp6, temp7;
     FLOAT sum0 = 0.0;
@@ -24,14 +24,14 @@ static FLOAT casum_kernel(BLASLONG n, FLOAT *x1)
     FLOAT sum4 = 0.0;
     
     while (i < n_8) {
-        temp0 = ABS_K(x[0]);
-        temp1 = ABS_K(x[1]);
-        temp2 = ABS_K(x[2]);
-        temp3 = ABS_K(x[3]);
-        temp4 = ABS_K(x[4]);
-        temp5 = ABS_K(x[5]);
-        temp6 = ABS_K(x[6]);
-        temp7 = ABS_K(x[7]);
+        temp0 = ABS_K(x1[0]);
+        temp1 = ABS_K(x1[1]);
+        temp2 = ABS_K(x1[2]);
+        temp3 = ABS_K(x1[3]);
+        temp4 = ABS_K(x1[4]);
+        temp5 = ABS_K(x1[5]);
+        temp6 = ABS_K(x1[6]);
+        temp7 = ABS_K(x1[7]);
         
         sum0 += temp0;
         sum1 += temp1;
@@ -43,12 +43,12 @@ static FLOAT casum_kernel(BLASLONG n, FLOAT *x1)
         sum2 += temp6;
         sum3 += temp7;
         
-        x+=8;
+        x1+=8;
         i+=4;
     }
 
      while (i < n) {
-        sum4 += (ABS_K(x1[0]) + ABS_K(x1[1]));
+        sum4 += ABS_K(x1[0]) + ABS_K(x1[1]);
         x1 += 2;
         i++;
      }