From 0ef4b3f1f2b8c4ea20afbd50c35d29971ea1c3e1 Mon Sep 17 00:00:00 2001
From: Martin Kroeker <martin@ruby.chemie.uni-freiburg.de>
Date: Sun, 2 Aug 2020 18:27:40 +0200
Subject: [PATCH] Multiply instead of doing a left shift of a potentially
 negative number

fixes GCC ubsan report in the BLAS tests
---
 kernel/x86_64/cgemv_t_4.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/x86_64/cgemv_t_4.c b/kernel/x86_64/cgemv_t_4.c
index 6bdea6787..f44fe7247 100644
--- a/kernel/x86_64/cgemv_t_4.c
+++ b/kernel/x86_64/cgemv_t_4.c
@@ -233,9 +233,9 @@ int CNAME(BLASLONG m, BLASLONG n, BLASLONG dummy1, FLOAT alpha_r, FLOAT alpha_i,
         if ( m < 1 ) return(0);
         if ( n < 1 ) return(0);
 
-        inc_x <<= 1;
-        inc_y <<= 1;
-        lda   <<= 1;
+        inc_x *= 2;
+        inc_y *= 2;
+        lda   *= 2;
 	lda4    = lda << 2;
 
 	xbuffer = buffer;