Hi, this patch has not changed since I posted it the last time (http://gcc.gnu.org/ml/gcc-patches/2012-02/msg01375.html) except for a fixed formatting of a comment. It has been already approved by Richi (http://gcc.gnu.org/ml/gcc-patches/2012-02/msg01389.html) and I intend to commit it this week even if the other patches still undergo review.
Thanks, Martin 2012-03-08 Martin Jambor <mjam...@suse.cz> * expr.c (expand_assignment): Handle misaligned scalar writes to memory through top-level MEM_REFs by calling store_bit_field. * testsuite/gcc.dg/misaligned-expand-2.c: New test. Index: src/gcc/expr.c =================================================================== --- src.orig/gcc/expr.c +++ src/gcc/expr.c @@ -4593,10 +4593,12 @@ expand_assignment (tree to, tree from, b if ((TREE_CODE (to) == MEM_REF || TREE_CODE (to) == TARGET_MEM_REF) && mode != BLKmode + && !mem_ref_refers_to_non_mem_p (to) && ((align = get_object_or_type_alignment (to)) < GET_MODE_ALIGNMENT (mode)) - && ((icode = optab_handler (movmisalign_optab, mode)) - != CODE_FOR_nothing)) + && (((icode = optab_handler (movmisalign_optab, mode)) + != CODE_FOR_nothing) + || SLOW_UNALIGNED_ACCESS (mode, align))) { addr_space_t as = TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (TREE_OPERAND (to, 0)))); @@ -4639,11 +4641,17 @@ expand_assignment (tree to, tree from, b if (TREE_THIS_VOLATILE (to)) MEM_VOLATILE_P (mem) = 1; - create_fixed_operand (&ops[0], mem); - create_input_operand (&ops[1], reg, mode); - /* The movmisalign<mode> pattern cannot fail, else the assignment would - silently be omitted. */ - expand_insn (icode, 2, ops); + if (icode != CODE_FOR_nothing) + { + create_fixed_operand (&ops[0], mem); + create_input_operand (&ops[1], reg, mode); + /* The movmisalign<mode> pattern cannot fail, else the assignment + would silently be omitted. */ + expand_insn (icode, 2, ops); + } + else + store_bit_field (mem, GET_MODE_BITSIZE (mode), + 0, 0, 0, mode, reg); return; } Index: src/gcc/testsuite/gcc.dg/misaligned-expand-2.c =================================================================== --- /dev/null +++ src/gcc/testsuite/gcc.dg/misaligned-expand-2.c @@ -0,0 +1,42 @@ +/* Test that expand can generate correct stores to misaligned data even on + strict alignment platforms. */ + +/* { dg-do run } */ +/* { dg-options "-O0" } */ + +extern void abort (); + +typedef unsigned int myint __attribute__((aligned(1))); + +void +foo (myint *p, unsigned int i) +{ + *p = i; +} + +#define cst 0xdeadbeef +#define NUM 8 + +struct blah +{ + char c; + myint i[NUM]; +}; + +struct blah g; + +#define cst 0xdeadbeef + +int +main (int argc, char **argv) +{ + int k; + + for (k = 0; k < NUM; k++) + { + foo (&g.i[k], cst); + if (g.i[k] != cst) + abort (); + } + return 0; +}