diff options
| author | Richard Kenner <kenner@gcc.gnu.org> | 1996-06-18 06:33:10 -0400 |
|---|---|---|
| committer | Richard Kenner <kenner@gcc.gnu.org> | 1996-06-18 06:33:10 -0400 |
| commit | 0b04ec8c2190fe80e0799c61f42549a6194e3979 (patch) | |
| tree | 9d26ee7e7eb897c8cdd301fa3f255406fc5fbaba /gcc/explow.c | |
| parent | 489af5d14b2291aa2e2118819060b12be7e1a0f8 (diff) | |
| download | gcc-0b04ec8c2190fe80e0799c61f42549a6194e3979.zip gcc-0b04ec8c2190fe80e0799c61f42549a6194e3979.tar.gz gcc-0b04ec8c2190fe80e0799c61f42549a6194e3979.tar.bz2 | |
(convert_memory_address, case PLUS, MULT): Don't commute operation
with extension if not adding small integer.
From-SVN: r12292
Diffstat (limited to 'gcc/explow.c')
| -rw-r--r-- | gcc/explow.c | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/gcc/explow.c b/gcc/explow.c index 8987075..b918294 100644 --- a/gcc/explow.c +++ b/gcc/explow.c @@ -304,8 +304,11 @@ convert_memory_address (to_mode, x) enum machine_mode to_mode; rtx x; { + enum machine_mode from_mode = to_mode == ptr_mode ? Pmode : ptr_mode; rtx temp; + /* Here we handle some special cases. If none of them apply, fall through + to the default case. */ switch (GET_CODE (x)) { case CONST_INT: @@ -320,21 +323,25 @@ convert_memory_address (to_mode, x) SYMBOL_REF_FLAG (temp) = SYMBOL_REF_FLAG (x); return temp; - case PLUS: - case MULT: - return gen_rtx (GET_CODE (x), to_mode, - convert_memory_address (to_mode, XEXP (x, 0)), - convert_memory_address (to_mode, XEXP (x, 1))); - case CONST: return gen_rtx (CONST, to_mode, convert_memory_address (to_mode, XEXP (x, 0))); - default: - return convert_modes (to_mode, - to_mode == ptr_mode ? Pmode : ptr_mode, - x, POINTERS_EXTEND_UNSIGNED); + case PLUS: + case MULT: + /* For addition the second operand is a small constant, we can safely + permute the converstion and addition operation. We can always safely + permute them if we are making the address narrower. */ + if (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (from_mode) + || (GET_CODE (x) == PLUS && GET_CODE (XEXP (x, 1)) == CONST_INT + && INTVAL (x) + 20000 < 40000)) + return gen_rtx (GET_CODE (x), to_mode, + convert_memory_address (to_mode, XEXP (x, 0)), + convert_memory_address (to_mode, XEXP (x, 1))); } + + return convert_modes (to_mode, from_mode, + x, POINTERS_EXTEND_UNSIGNED); } #endif |