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| author | Richard Kenner <kenner@gcc.gnu.org> | 1993-10-07 08:14:16 -0400 |
|---|---|---|
| committer | Richard Kenner <kenner@gcc.gnu.org> | 1993-10-07 08:14:16 -0400 |
| commit | ceb7983c7c9d08b444761ebbb375e12ca78a5852 (patch) | |
| tree | b1b45fc0fabfddb319f16ec433176ea615e075fd | |
| parent | 7be2640ddbc65bfc504351af589d0ba84e50d4f4 (diff) | |
| download | gcc-ceb7983c7c9d08b444761ebbb375e12ca78a5852.zip gcc-ceb7983c7c9d08b444761ebbb375e12ca78a5852.tar.gz gcc-ceb7983c7c9d08b444761ebbb375e12ca78a5852.tar.bz2 | |
(force_to_mode): Sign-extend constant being truncated.
From-SVN: r5654
| -rw-r--r-- | gcc/combine.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index 8f9efb8..abc224c 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -5614,7 +5614,18 @@ force_to_mode (x, mode, mask, reg) /* If X is a CONST_INT, return a new one. Do this here since the test below will fail. */ if (GET_CODE (x) == CONST_INT) - return GEN_INT (INTVAL (x) & mask); + { + HOST_WIDE_INT cval = INTVAL (x) & mask; + int width = GET_MODE_BITSIZE (mode); + + /* If MODE is narrower that HOST_WIDE_INT and CVAL is a negative + number, sign extend it. */ + if (width > 0 && width < HOST_BITS_PER_WIDE_INT + && (cval & ((HOST_WIDE_INT) 1 << (width - 1))) != 0) + cval |= (HOST_WIDE_INT) -1 << width; + + return GEN_INT (cval); + } /* If X is narrower than MODE, just get X in the proper mode. */ if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (mode)) |