diff options
Diffstat (limited to 'gcc/alias.c')
-rw-r--r-- | gcc/alias.c | 43 |
1 files changed, 41 insertions, 2 deletions
diff --git a/gcc/alias.c b/gcc/alias.c index 719b8901d15..909176ea3fb 100644 --- a/gcc/alias.c +++ b/gcc/alias.c @@ -860,6 +860,45 @@ base_alias_check (x, y, x_mode, y_mode) return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode); } +/* Return the address of the (N_REFS + 1)th memory reference to ADDR + where SIZE is the size in bytes of the memory reference. If ADDR + is not modified by the memory reference then ADDR is returned. */ + +rtx +addr_side_effect_eval (addr, size, n_refs) + rtx addr; + int size; + int n_refs; +{ + int offset = 0; + + switch (GET_CODE (addr)) + { + case PRE_INC: + offset = (n_refs + 1) * size; + break; + case PRE_DEC: + offset = -(n_refs + 1) * size; + break; + case POST_INC: + offset = n_refs * size; + break; + case POST_DEC: + offset = -n_refs * size; + break; + + default: + return addr; + } + + if (offset) + addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), GEN_INT (offset)); + else + addr = XEXP (addr, 0); + + return addr; +} + /* Return nonzero if X and Y (memory addresses) could reference the same location in memory. C is an offset accumulator. When C is nonzero, we are testing aliases between X and Y + C. @@ -889,13 +928,13 @@ memrefs_conflict_p (xsize, x, ysize, y, c) else if (GET_CODE (x) == LO_SUM) x = XEXP (x, 1); else - x = canon_rtx (x); + x = canon_rtx (addr_side_effect_eval (x, xsize, 0)); if (GET_CODE (y) == HIGH) y = XEXP (y, 0); else if (GET_CODE (y) == LO_SUM) y = XEXP (y, 1); else - y = canon_rtx (y); + y = canon_rtx (addr_side_effect_eval (y, ysize, 0)); if (rtx_equal_for_memref_p (x, y)) { |