From c5fb91f1bc19baac6c874e6a41fd107c40187278 Mon Sep 17 00:00:00 2001
From: Martin Kroeker <martin@ruby.chemie.uni-freiburg.de>
Date: Thu, 29 Apr 2021 09:47:18 +0200
Subject: [PATCH] Fix division by zero in the non-x86 codepath

---
 interface/zrotg.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/interface/zrotg.c b/interface/zrotg.c
index 8caa411..bc4f064 100644
--- a/interface/zrotg.c
+++ b/interface/zrotg.c
@@ -79,8 +79,12 @@ void NAME(FLOAT *DA, FLOAT *DB, FLOAT *C, FLOAT *S){
       aa_i = fabs(da_r);
     }
 
-    scale = (aa_i / aa_r);
-    ada = aa_r * sqrt(ONE + scale * scale);
+    if (aa_r == ZERO) {
+	ada = 0.;
+    } else {
+        scale = (aa_i / aa_r);
+        ada = aa_r * sqrt(ONE + scale * scale);
+    }
 
     bb_r = fabs(db_r);
     bb_i = fabs(db_i);
@@ -90,9 +94,12 @@ void NAME(FLOAT *DA, FLOAT *DB, FLOAT *C, FLOAT *S){
       bb_i = fabs(bb_r);
     }
 
-    scale = (bb_i / bb_r);
-    adb = bb_r * sqrt(ONE + scale * scale);
-
+    if (bb_r == ZERO) {
+	adb = 0.;
+    } else {
+    	scale = (bb_i / bb_r);
+    	adb = bb_r * sqrt(ONE + scale * scale);
+    }
     scale = ada + adb;
 
     aa_r    = da_r / scale;
-- 
2.7.4