swscale: fix crash in fast_bilinear code when compiled with -mred-zone.

Additional comments from Måns Rullgard have been integrated
by Reinhard Tartler.
Signed-off-by: Reinhard Tartler <siretart@tauware.de>

libswscale/x86/swscale_template.c

@@ -1513,12 +1513,24 @@ static void RENAME(hyscale_fast)(SwsContext *c, int16_t *dst,
     void    *mmx2FilterCode= c->lumMmx2FilterCode;
     int i;
 #if defined(PIC)
-    DECLARE_ALIGNED(8, uint64_t, ebxsave);
+    uint64_t ebxsave;
+#endif
+#if ARCH_X86_64
+    uint64_t retsave;
 #endif
 
     __asm__ volatile(
 #if defined(PIC)
         "mov               %%"REG_b", %5        \n\t"
+#if ARCH_X86_64
+        "mov               -8(%%rsp), %%"REG_a" \n\t"
+        "mov               %%"REG_a", %6        \n\t"
+#endif
+#else
+#if ARCH_X86_64
+        "mov               -8(%%rsp), %%"REG_a" \n\t"
+        "mov               %%"REG_a", %5        \n\t"
+#endif
 #endif
         "pxor                  %%mm7, %%mm7     \n\t"
         "mov                      %0, %%"REG_c" \n\t"
@@ -1560,11 +1572,23 @@ static void RENAME(hyscale_fast)(SwsContext *c, int16_t *dst,
 
 #if defined(PIC)
         "mov                      %5, %%"REG_b" \n\t"
+#if ARCH_X86_64
+        "mov                      %6, %%"REG_a" \n\t"
+        "mov               %%"REG_a", -8(%%rsp) \n\t"
+#endif
+#else
+#if ARCH_X86_64
+        "mov                      %5, %%"REG_a" \n\t"
+        "mov               %%"REG_a", -8(%%rsp) \n\t"
+#endif
 #endif
         :: "m" (src), "m" (dst), "m" (filter), "m" (filterPos),
            "m" (mmx2FilterCode)
 #if defined(PIC)
           ,"m" (ebxsave)
+#endif
+#if ARCH_X86_64
+          ,"m"(retsave)
 #endif
         : "%"REG_a, "%"REG_c, "%"REG_d, "%"REG_S, "%"REG_D
 #if !defined(PIC)
@@ -1587,10 +1611,22 @@ static void RENAME(hcscale_fast)(SwsContext *c, int16_t *dst1, int16_t *dst2,
 #if defined(PIC)
     DECLARE_ALIGNED(8, uint64_t, ebxsave);
 #endif
+#if ARCH_X86_64
+    DECLARE_ALIGNED(8, uint64_t, retsave);
+#endif
 
     __asm__ volatile(
 #if defined(PIC)
         "mov          %%"REG_b", %7         \n\t"
+#if ARCH_X86_64
+        "mov          -8(%%rsp), %%"REG_a"  \n\t"
+        "mov          %%"REG_a", %8         \n\t"
+#endif
+#else
+#if ARCH_X86_64
+        "mov          -8(%%rsp), %%"REG_a"  \n\t"
+        "mov          %%"REG_a", %7         \n\t"
+#endif
 #endif
         "pxor             %%mm7, %%mm7      \n\t"
         "mov                 %0, %%"REG_c"  \n\t"
@@ -1620,11 +1656,23 @@ static void RENAME(hcscale_fast)(SwsContext *c, int16_t *dst1, int16_t *dst2,
 
 #if defined(PIC)
         "mov %7, %%"REG_b"    \n\t"
+#if ARCH_X86_64
+        "mov                 %8, %%"REG_a"  \n\t"
+        "mov          %%"REG_a", -8(%%rsp)  \n\t"
+#endif
+#else
+#if ARCH_X86_64
+        "mov                 %7, %%"REG_a"  \n\t"
+        "mov          %%"REG_a", -8(%%rsp)  \n\t"
+#endif
 #endif
         :: "m" (src1), "m" (dst1), "m" (filter), "m" (filterPos),
            "m" (mmx2FilterCode), "m" (src2), "m"(dst2)
 #if defined(PIC)
           ,"m" (ebxsave)
+#endif
+#if ARCH_X86_64
+          ,"m"(retsave)
 #endif
         : "%"REG_a, "%"REG_c, "%"REG_d, "%"REG_S, "%"REG_D
 #if !defined(PIC)