From 37de2b5c1e370b493932552556940eb89922b027 Mon Sep 17 00:00:00 2001
From: Andy Polyakov <appro@openssl.org>
Date: Wed, 9 Oct 2013 11:08:52 +0200
Subject: bn/bn_exp.c: prefer MULX/AD*X over AVX2.

---
 crypto/bn/bn_exp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'crypto')

diff --git a/crypto/bn/bn_exp.c b/crypto/bn/bn_exp.c
index cfbaf2b66f..6e3a7264d5 100644
--- a/crypto/bn/bn_exp.c
+++ b/crypto/bn/bn_exp.c
@@ -691,7 +691,8 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p,
 	 * RSAZ exponentiation. For further information see
 	 * crypto/bn/rsaz_exp.c and accompanying assembly modules.
 	 */
-	if ((16 == a->top) && (16 == p->top) && (BN_num_bits(m) == 1024)
+	if (((OPENSSL_ia32cap_P[2]&0x80100) != 0x80100) /* check for MULX/AD*X */
+	    && (16 == a->top) && (16 == p->top) && (BN_num_bits(m) == 1024)
 	    && rsaz_avx2_eligible())
 	    	{
 		if (NULL == bn_wexpand(rr, 16)) goto err;
-- 
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