--- gcc/config/i386.h	2018/04/24 17:51:31	1.1
+++ gcc/config/i386.h	2018/04/24 17:53:46	1.1.1.2
@@ -19,7 +19,7 @@ the Free Software Foundation, 675 Mass A
 
 
 /* The purpose of this file is to define the characteristics of the i386,
-   independant of assembler syntax or operating system.
+   independent of assembler syntax or operating system.
 
    Three other files build on this one to describe a specific assembler syntax:
    bsd386.h, att386.h, and sun386.h.
@@ -91,7 +91,7 @@ extern int target_flags;
 /* Not true for 80386 */
 #define WORDS_BIG_ENDIAN 0
 
-/* number of bits in an addressible storage unit */
+/* number of bits in an addressable storage unit */
 #define BITS_PER_UNIT 8
 
 /* Width in bits of a "word", which is the contents of a machine register.
@@ -129,9 +129,9 @@ extern int target_flags;
    quantities, but these can be aligned on any 32-bit boundary.  */
 #define BIGGEST_ALIGNMENT 32
 
-/* Define this if move instructions will actually fail to work
+/* Set this non-zero if move instructions will actually fail to work
    when given unaligned data.  */
-/* #define STRICT_ALIGNMENT */
+#define STRICT_ALIGNMENT 0
 
 /* If bit field type is int, don't let it cross an int,
    and give entire struct the alignment of an int.  */
@@ -309,13 +309,16 @@ extern int target_flags;
    in a smaller-numbered class.
 
    For any two classes, it is very desirable that there be another
-   class that represents their union.  */
-   
+   class that represents their union.
+
+   It might seem that class BREG is unnecessary, since no useful 386
+   opcode needs reg %ebx.  But some systems pass args to the OS in ebx,
+   and the "b" register constraint is useful in asms for syscalls.  */
 
 enum reg_class
 {
   NO_REGS,
-  AREG, DREG, CREG,
+  AREG, DREG, CREG, BREG,
   Q_REGS,			/* %eax %ebx %ecx %edx */
   SIREG, DIREG,
   INDEX_REGS,			/* %eax %ebx %ecx %edx %esi %edi %ebp */
@@ -331,7 +334,7 @@ enum reg_class
 
 #define REG_CLASS_NAMES \
 {  "NO_REGS",				\
-   "AREG", "DREG", "CREG",		\
+   "AREG", "DREG", "CREG", "BREG",	\
    "Q_REGS",				\
    "SIREG", "DIREG",			\
    "INDEX_REGS",			\
@@ -346,7 +349,7 @@ enum reg_class
 
 #define REG_CLASS_CONTENTS \
 {      0,							\
-     0x1,    0x2,  0x4,		/* AREG, DREG, CREG */		\
+     0x1,    0x2,  0x4,	 0x8,	/* AREG, DREG, CREG, BREG */	\
      0xf,			/* Q_REGS */			\
     0x10,   0x20,		/* SIREG, DIREG */		\
  0x1007f,			/* INDEX_REGS */		\
@@ -409,6 +412,7 @@ extern enum reg_class regclass_map[FIRST
    (C) == 't' ? FP_TOP_REG :		\
    (C) == 'u' ? FP_SECOND_REG :		\
    (C) == 'a' ? AREG :			\
+   (C) == 'b' ? BREG :			\
    (C) == 'c' ? CREG :			\
    (C) == 'd' ? DREG :			\
    (C) == 'D' ? DIREG :			\
@@ -435,10 +439,12 @@ extern enum reg_class regclass_map[FIRST
    0)
 
 /* Similar, but for floating constants, and defining letters G and H.
-   Here VALUE is the CONST_DOUBLE rtx itself.  */
+   Here VALUE is the CONST_DOUBLE rtx itself.  We allow constants even if
+   TARGET_387 isn't set, because the stack register converter may need to
+   load 0.0 into the function value register. */
 
 #define CONST_DOUBLE_OK_FOR_LETTER_P(VALUE, C)  \
-  ((C) == 'G' ? (TARGET_80387 && standard_80387_constant_p (VALUE)) : 0)
+  ((C) == 'G' ? standard_80387_constant_p (VALUE) : 0)
 
 /* Place additional restrictions on the register class to use when it
    is necessary to be able to hold a value of mode @var{mode} in a reload
@@ -988,7 +994,7 @@ do {						\
    differently depending on something about the variable or
    function named by the symbol (such as what section it is in).
 
-   On i386, if using PIC, mark a SYMBOL_REF for a static declaration
+   On i386, if using PIC, mark a SYMBOL_REF for a non-global symbol
    so that we may access it directly in the GOT.  */
 
 #define ENCODE_SECTION_INFO(DECL) \
@@ -996,9 +1002,11 @@ do									\
   {									\
     if (flag_pic)							\
       {									\
-	rtx decl_rtl = (TREE_CODE_CLASS (TREE_CODE (DECL)) == 'c'	\
-			? TREE_CST_RTL (DECL) : DECL_RTL (DECL));	\
-	SYMBOL_REF_FLAG (XEXP (decl_rtl, 0)) = ! TREE_PUBLIC (DECL);	\
+	rtx rtl = (TREE_CODE_CLASS (TREE_CODE (DECL)) != 'd'		\
+		   ? TREE_CST_RTL (DECL) : DECL_RTL (DECL));		\
+	SYMBOL_REF_FLAG (XEXP (rtl, 0))					\
+	  = (TREE_CODE_CLASS (TREE_CODE (DECL)) != 'd'			\
+	     || ! TREE_PUBLIC (DECL));					\
       }									\
   }									\
 while (0)
@@ -1201,7 +1209,7 @@ to get gcc to use these, since they want
 number as al, and ax.
 */
 
-/* note the last four are not really qi_registsers, but
+/* note the last four are not really qi_registers, but
    the md will have to never output movb into one of them
    only a movw .  There is no movb into the last four regs */