From 559ee1e940c22a49ac8a39f6053917533e71243a Mon Sep 17 00:00:00 2001
From: grischka <grischka>
Date: Mon, 19 Dec 2016 00:27:08 +0100
Subject: i386-gen: fix USE_EBX

Restore ebx from *ebp because alloca might change esp.

Also disable USE_EBX for upcoming release.

Actually the benefit is less than one would expect, it
appears that tcc can't do much with more than 3 registers
except with extensive use of long longs where the disassembly
looks much prettier (and shorter also).

Also: tccgen/expr_cond() : fix wrong gv/save_regs order
---
 i386-gen.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

(limited to 'i386-gen.c')

diff --git a/i386-gen.c b/i386-gen.c
index 3a26f7a..946e42d 100644
--- a/i386-gen.c
+++ b/i386-gen.c
@@ -79,7 +79,7 @@ enum {
 #include "tcc.h"
 
 /* define to 1/0 to [not] have EBX as 4th register */
-#define USE_EBX 1
+#define USE_EBX 0
 
 ST_DATA const int reg_classes[NB_REGS] = {
     /* eax */ RC_INT | RC_EAX,
@@ -636,7 +636,15 @@ ST_FUNC void gfunc_epilog(void)
         o(0x585a); /* restore returned value, if any */
     }
 #endif
-    o(0x5b * USE_EBX); /* pop ebx */
+
+    /* align local size to word & save local variables */
+    v = (-loc + 3) & -4;
+
+#if USE_EBX
+    o(0x8b);
+    gen_modrm(TREG_EBX, VT_LOCAL, NULL, -(v+4));
+#endif
+
     o(0xc9); /* leave */
     if (func_ret_sub == 0) {
         o(0xc3); /* ret */
@@ -645,9 +653,6 @@ ST_FUNC void gfunc_epilog(void)
         g(func_ret_sub);
         g(func_ret_sub >> 8);
     }
-    /* align local size to word & save local variables */
-    
-    v = (-loc + 3) & -4; 
     saved_ind = ind;
     ind = func_sub_sp_offset - FUNC_PROLOG_SIZE;
 #ifdef TCC_TARGET_PE
-- 
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