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| author | Richard Kenner <kenner@gcc.gnu.org> | 1994-05-05 14:37:00 -0400 |
|---|---|---|
| committer | Richard Kenner <kenner@gcc.gnu.org> | 1994-05-05 14:37:00 -0400 |
| commit | 87e3e0c1b502d3cbb316cd32745eb1fc4542a540 (patch) | |
| tree | d3253a207d9e3b252e59fd090297a29b8aef3417 | |
| parent | 83a24b1d0d7894b76f1ad1e31dd149f2c6a79baf (diff) | |
| download | gcc-87e3e0c1b502d3cbb316cd32745eb1fc4542a540.zip gcc-87e3e0c1b502d3cbb316cd32745eb1fc4542a540.tar.gz gcc-87e3e0c1b502d3cbb316cd32745eb1fc4542a540.tar.bz2 | |
(simplify_rtx, case SUBREG): Don't call force_to_mode.
(simplify_set): Call force_to_mode here.
From-SVN: r7216
| -rw-r--r-- | gcc/combine.c | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index 41c83dc..3201096 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -3260,16 +3260,10 @@ simplify_rtx (x, op0_mode, last, in_dest) && GET_MODE_SIZE (mode) > GET_MODE_SIZE (op0_mode)) return SUBREG_REG (x); - /* If we are narrowing an integral object, we need to see if we can - simplify the expression for the object knowing that we only need the - low-order bits. */ + /* Note that we cannot do any narrowing for non-constants since + we might have been counting on using the fact that some bits were + zero. We now do this in the SET. */ - if (GET_MODE_CLASS (mode) == MODE_INT - && GET_MODE_CLASS (GET_MODE (SUBREG_REG (x))) == MODE_INT - && GET_MODE_SIZE (mode) < GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))) - && subreg_lowpart_p (x)) - return force_to_mode (SUBREG_REG (x), mode, GET_MODE_MASK (mode), - NULL_RTX, 0); break; case NOT: @@ -4201,6 +4195,13 @@ simplify_set (x) if (GET_CODE (dest) == PC && GET_CODE (src) == RETURN) return src; + /* Now that we know for sure which bits of SRC we are using, see if we can + simplify the expression for the object knowing that we only need the + low-order bits. */ + + if (GET_MODE_CLASS (mode) == MODE_INT) + src = force_to_mode (src, mode, GET_MODE_MASK (mode), NULL_RTX, 0); + /* Convert this into a field assignment operation, if possible. */ x = make_field_assignment (x); |