commit 7f329a2f9c3efdb5e7a6483792fcfab945cc7a84
Author: Kyrylo Tkachov <kyrylo.tkachov@arm.com>
Date:   Wed Oct 28 17:29:18 2015 +0000

    [ARM] Properly update memory offsets when expanding setmem

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index d0fe028..8a92798 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -29171,7 +29171,7 @@ arm_block_set_unaligned_vect (rtx dstbase,
   rtx (*gen_func) (rtx, rtx);
   machine_mode mode;
   unsigned HOST_WIDE_INT v = value;
-
+  unsigned int offset = 0;
   gcc_assert ((align & 0x3) != 0);
   nelt_v8 = GET_MODE_NUNITS (V8QImode);
   nelt_v16 = GET_MODE_NUNITS (V16QImode);
@@ -29192,7 +29192,7 @@ arm_block_set_unaligned_vect (rtx dstbase,
     return false;
 
   dst = copy_addr_to_reg (XEXP (dstbase, 0));
-  mem = adjust_automodify_address (dstbase, mode, dst, 0);
+  mem = adjust_automodify_address (dstbase, mode, dst, offset);
 
   v = sext_hwi (v, BITS_PER_WORD);
   val_elt = GEN_INT (v);
@@ -29209,7 +29209,11 @@ arm_block_set_unaligned_vect (rtx dstbase,
     {
       emit_insn ((*gen_func) (mem, reg));
       if (i + 2 * nelt_mode <= length)
-	emit_insn (gen_add2_insn (dst, GEN_INT (nelt_mode)));
+	{
+	  emit_insn (gen_add2_insn (dst, GEN_INT (nelt_mode)));
+	  offset += nelt_mode;
+	  mem = adjust_automodify_address (dstbase, mode, dst, offset);
+	}
     }
 
   /* If there are not less than nelt_v8 bytes leftover, we must be in
@@ -29220,6 +29224,9 @@ arm_block_set_unaligned_vect (rtx dstbase,
   if (i + nelt_v8 < length)
     {
       emit_insn (gen_add2_insn (dst, GEN_INT (length - i)));
+      offset += length - i;
+      mem = adjust_automodify_address (dstbase, mode, dst, offset);
+
       /* We are shifting bytes back, set the alignment accordingly.  */
       if ((length & 1) != 0 && align >= 2)
 	set_mem_align (mem, BITS_PER_UNIT);
@@ -29230,12 +29237,13 @@ arm_block_set_unaligned_vect (rtx dstbase,
   else if (i < length && i + nelt_v8 >= length)
     {
       if (mode == V16QImode)
-	{
-	  reg = gen_lowpart (V8QImode, reg);
-	  mem = adjust_automodify_address (dstbase, V8QImode, dst, 0);
-	}
+	reg = gen_lowpart (V8QImode, reg);
+
       emit_insn (gen_add2_insn (dst, GEN_INT ((length - i)
 					      + (nelt_mode - nelt_v8))));
+      offset += (length - i) + (nelt_mode - nelt_v8);
+      mem = adjust_automodify_address (dstbase, V8QImode, dst, offset);
+
       /* We are shifting bytes back, set the alignment accordingly.  */
       if ((length & 1) != 0 && align >= 2)
 	set_mem_align (mem, BITS_PER_UNIT);
@@ -29262,6 +29270,7 @@ arm_block_set_aligned_vect (rtx dstbase,
   rtx rval[MAX_VECT_LEN];
   machine_mode mode;
   unsigned HOST_WIDE_INT v = value;
+  unsigned int offset = 0;
 
   gcc_assert ((align & 0x3) == 0);
   nelt_v8 = GET_MODE_NUNITS (V8QImode);
@@ -29293,14 +29302,15 @@ arm_block_set_aligned_vect (rtx dstbase,
   /* Handle first 16 bytes specially using vst1:v16qi instruction.  */
   if (mode == V16QImode)
     {
-      mem = adjust_automodify_address (dstbase, mode, dst, 0);
+      mem = adjust_automodify_address (dstbase, mode, dst, offset);
       emit_insn (gen_movmisalignv16qi (mem, reg));
       i += nelt_mode;
       /* Handle (8, 16) bytes leftover using vst1:v16qi again.  */
       if (i + nelt_v8 < length && i + nelt_v16 > length)
 	{
 	  emit_insn (gen_add2_insn (dst, GEN_INT (length - nelt_mode)));
-	  mem = adjust_automodify_address (dstbase, mode, dst, 0);
+	  offset += length - nelt_mode;
+	  mem = adjust_automodify_address (dstbase, mode, dst, offset);
 	  /* We are shifting bytes back, set the alignment accordingly.  */
 	  if ((length & 0x3) == 0)
 	    set_mem_align (mem, BITS_PER_UNIT * 4);
@@ -29322,7 +29332,7 @@ arm_block_set_aligned_vect (rtx dstbase,
   for (; (i + nelt_mode <= length); i += nelt_mode)
     {
       addr = plus_constant (Pmode, dst, i);
-      mem = adjust_automodify_address (dstbase, mode, addr, i);
+      mem = adjust_automodify_address (dstbase, mode, addr, offset + i);
       emit_move_insn (mem, reg);
     }
 
@@ -29331,8 +29341,8 @@ arm_block_set_aligned_vect (rtx dstbase,
   if (i + UNITS_PER_WORD == length)
     {
       addr = plus_constant (Pmode, dst, i - UNITS_PER_WORD);
-      mem = adjust_automodify_address (dstbase, mode,
-				       addr, i - UNITS_PER_WORD);
+      offset += i - UNITS_PER_WORD;
+      mem = adjust_automodify_address (dstbase, mode, addr, offset);
       /* We are shifting 4 bytes back, set the alignment accordingly.  */
       if (align > UNITS_PER_WORD)
 	set_mem_align (mem, BITS_PER_UNIT * UNITS_PER_WORD);
@@ -29344,7 +29354,8 @@ arm_block_set_aligned_vect (rtx dstbase,
   else if (i < length)
     {
       emit_insn (gen_add2_insn (dst, GEN_INT (length - nelt_mode)));
-      mem = adjust_automodify_address (dstbase, mode, dst, 0);
+      offset += length - nelt_mode;
+      mem = adjust_automodify_address (dstbase, mode, dst, offset);
       /* We are shifting bytes back, set the alignment accordingly.  */
       if ((length & 1) == 0)
 	set_mem_align (mem, BITS_PER_UNIT * 2);
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr68143_1.c b/gcc/testsuite/gcc.c-torture/execute/pr68143_1.c
new file mode 100644
index 0000000..cbfbbc2
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr68143_1.c
@@ -0,0 +1,31 @@
+#define NULL 0
+
+struct stuff
+{
+    int a;
+    int b;
+    int c;
+    int d;
+    int e;
+    char *f;
+    int g;
+};
+
+void __attribute__ ((noinline))
+bar (struct stuff *x)
+{
+  if (x->g != 2)
+    __builtin_abort ();
+}
+
+int
+main (int argc, char** argv)
+{
+  struct stuff x = {0, 0, 0, 0, 0, NULL, 0};
+  x.a = 100;
+  x.d = 100;
+  x.g = 2;
+  /* Struct should now look like {100, 0, 0, 100, 0, 0, 0, 2}.  */
+  bar (&x);
+  return 0;
+}
