From: Matt Caswell <matt@openssl.org>
Date: Wed, 31 Jan 2018 13:37:42 +0000 (+0000)
Subject: Remove unrolled loops
X-Git-Tag: OpenSSL_1_1_1-pre2~61
X-Git-Url: https://git.openssl.org/?p=openssl.git;a=commitdiff_plain;h=cb5ed32665ffb3a5ed6f631343d9c5302eaf7478

Remove unrolled loops

Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/5105)
---

diff --git a/crypto/ec/curve448/arch_32/f_impl.c b/crypto/ec/curve448/arch_32/f_impl.c
index 8ba7c630e7..423e8a803a 100644
--- a/crypto/ec/curve448/arch_32/f_impl.c
+++ b/crypto/ec/curve448/arch_32/f_impl.c
@@ -12,14 +12,6 @@
 
 #include "field.h"
 
-#if (defined(__OPTIMIZE__) && !defined(__OPTIMIZE_SIZE__) && !defined(I_HATE_UNROLLED_LOOPS)) \
-     || defined(C448_FORCE_UNROLL)
-# define REPEAT8(_x) _x _x _x _x _x _x _x _x
-# define FOR_LIMB(_i,_start,_end,_x) do { _i=_start; REPEAT8( if (_i<_end) { _x; } _i++;) } while (0)
-#else
-# define FOR_LIMB(_i,_start,_end,_x) do { for (_i=_start; _i<_end; _i++) _x; } while (0)
-#endif
-
 void gf_mul(gf_s * RESTRICT cs, const gf as, const gf bs)
 {
     const uint32_t *a = as->limb, *b = bs->limb;
@@ -34,30 +26,28 @@ void gf_mul(gf_s * RESTRICT cs, const gf as, const gf bs)
         bb[i] = b[i] + b[i + 8];
     }
 
-    FOR_LIMB(j, 0, 8, {
-             accum2 = 0;
-             FOR_LIMB(i, 0, j + 1, {
-                      accum2 += widemul(a[j - i], b[i]);
-                      accum1 += widemul(aa[j - i], bb[i]);
-                      accum0 += widemul(a[8 + j - i], b[8 + i]);
-                      }
-             ); accum1 -= accum2; accum0 += accum2;
-             accum2 = 0;
-             FOR_LIMB(i, j + 1, 8, {
-                      accum0 -=
-                      widemul(a[8 + j - i], b[i]);
-                      accum2 +=
-                      widemul(aa[8 + j - i],
-                              bb[i]);
-                      accum1 += widemul(a[16 + j - i], b[8 + i]);
-                      }
-             );
-             accum1 += accum2;
-             accum0 += accum2;
-             c[j] = ((uint32_t)(accum0)) & mask;
-             c[j + 8] = ((uint32_t)(accum1)) & mask;
-             accum0 >>= 28; accum1 >>= 28;
-             });
+    for (j = 0; j < 8; j++) {
+        accum2 = 0;
+        for (i = 0; i < j + 1; i++) {
+            accum2 += widemul(a[j - i], b[i]);
+            accum1 += widemul(aa[j - i], bb[i]);
+            accum0 += widemul(a[8 + j - i], b[8 + i]);
+        }
+        accum1 -= accum2;
+        accum0 += accum2;
+        accum2 = 0;
+        for (i = j + 1; i < 8; i++) {
+            accum0 -= widemul(a[8 + j - i], b[i]);
+            accum2 += widemul(aa[8 + j - i], bb[i]);
+            accum1 += widemul(a[16 + j - i], b[8 + i]);
+        }
+        accum1 += accum2;
+        accum0 += accum2;
+        c[j] = ((uint32_t)(accum0)) & mask;
+        c[j + 8] = ((uint32_t)(accum1)) & mask;
+        accum0 >>= 28;
+        accum1 >>= 28;
+    }
 
     accum0 += accum1;
     accum0 += c[8];
@@ -81,11 +71,14 @@ void gf_mulw_unsigned(gf_s * RESTRICT cs, const gf as, uint32_t b)
 
     assert(b < 1 << 28);
 
-    FOR_LIMB(i, 0, 8, {
-             accum0 += widemul(b, a[i]); accum8 += widemul(b, a[i + 8]);
-             c[i] = accum0 & mask; accum0 >>= 28;
-             c[i + 8] = accum8 & mask; accum8 >>= 28;
-             });
+    for (i = 0; i < 8; i++) {
+        accum0 += widemul(b, a[i]);
+        accum8 += widemul(b, a[i + 8]);
+        c[i] = accum0 & mask;
+        accum0 >>= 28;
+        c[i + 8] = accum8 & mask;
+        accum8 >>= 28;
+    }
 
     accum0 += accum8 + c[8];
     c[8] = ((uint32_t)accum0) & mask;
diff --git a/crypto/ec/curve448/f_generic.c b/crypto/ec/curve448/f_generic.c
index 341eb3f3b0..6babea6e41 100644
--- a/crypto/ec/curve448/f_generic.c
+++ b/crypto/ec/curve448/f_generic.c
@@ -30,7 +30,7 @@ void gf_serialize(uint8_t serial[SER_BYTES], const gf x, int with_hibit)
     if (!with_hibit)
         assert(gf_hibit(red) == 0);
 
-    UNROLL for (i = 0; i < (with_hibit ? X_SER_BYTES : SER_BYTES); i++) {
+    for (i = 0; i < (with_hibit ? X_SER_BYTES : SER_BYTES); i++) {
         if (fill < 8 && j < NLIMBS) {
             buffer |= ((dword_t) red->limb[LIMBPERM(j)]) << fill;
             fill += LIMB_PLACE_VALUE(LIMBPERM(j));
@@ -73,9 +73,11 @@ mask_t gf_deserialize(gf x, const uint8_t serial[SER_BYTES], int with_hibit,
     unsigned int i;
     mask_t succ;
 
-    UNROLL for (i = 0; i < NLIMBS; i++) {
-        UNROLL while (fill < LIMB_PLACE_VALUE(LIMBPERM(i)) && j < nbytes) {
-            uint8_t sj = serial[j];
+    for (i = 0; i < NLIMBS; i++) {
+        while (fill < LIMB_PLACE_VALUE(LIMBPERM(i)) && j < nbytes) {
+            uint8_t sj;
+
+            sj = serial[j];
             if (j == nbytes - 1)
                 sj &= ~hi_nmask;
             buffer |= ((dword_t) sj) << fill;
diff --git a/crypto/ec/curve448/word.h b/crypto/ec/curve448/word.h
index 6067404e65..c739b70d51 100644
--- a/crypto/ec/curve448/word.h
+++ b/crypto/ec/curve448/word.h
@@ -59,18 +59,6 @@ typedef int64_t dsword_t;
 #  error "For now we only support 32- and 64-bit architectures."
 # endif
 
-
-/* PERF: vectorize vs unroll */
-# ifdef __clang__
-#  if 100*__clang_major__ + __clang_minor__ > 305
-#   define UNROLL _Pragma("clang loop unroll(full)")
-#  endif
-# endif
-
-# ifndef UNROLL
-#  define UNROLL
-# endif
-
 /*
  * The plan on booleans: The external interface uses c448_bool_t, but this
  * might be a different size than our particular arch's word_t (and thus