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| author | J"orn Rennecke <amylaar@cygnus.co.uk> | 1998-05-21 11:35:10 +0000 |
|---|---|---|
| committer | Joern Rennecke <amylaar@gcc.gnu.org> | 1998-05-21 12:35:10 +0100 |
| commit | b52ce03da5fcaf93480c6f0d95e9be500a97fb33 (patch) | |
| tree | 431dc6bf5789b9644883f3f5629c6b90c7570170 /gcc/combine.c | |
| parent | d4dfe7d66cd2d6141684e2b686a4c3bc7bddbf39 (diff) | |
| download | gcc-b52ce03da5fcaf93480c6f0d95e9be500a97fb33.zip gcc-b52ce03da5fcaf93480c6f0d95e9be500a97fb33.tar.gz gcc-b52ce03da5fcaf93480c6f0d95e9be500a97fb33.tar.bz2 | |
combine.c (nonzero_bits): For paradoxical subregs, take LOAD_EXTENDED_OP into account.
* combine.c (nonzero_bits): For paradoxical subregs, take
LOAD_EXTENDED_OP into account.
From-SVN: r19928
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index 68c084f..14da483 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -7693,15 +7693,23 @@ nonzero_bits (x, mode) { nonzero &= nonzero_bits (SUBREG_REG (x), mode); -#ifndef WORD_REGISTER_OPERATIONS - /* On many CISC machines, accessing an object in a wider mode - causes the high-order bits to become undefined. So they are - not known to be zero. */ - if (GET_MODE_SIZE (GET_MODE (x)) - > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))) - nonzero |= (GET_MODE_MASK (GET_MODE (x)) - & ~ GET_MODE_MASK (GET_MODE (SUBREG_REG (x)))); +#if defined (WORD_REGISTER_OPERATIONS) && defined (LOAD_EXTEND_OP) + /* If this is a typical RISC machine, we only have to worry + about the way loads are extended. */ + if (LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (x))) == SIGN_EXTEND + ? (nonzero + & (1L << (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) - 1))) + : LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (x))) != ZERO_EXTEND) #endif + { + /* On many CISC machines, accessing an object in a wider mode + causes the high-order bits to become undefined. So they are + not known to be zero. */ + if (GET_MODE_SIZE (GET_MODE (x)) + > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))) + nonzero |= (GET_MODE_MASK (GET_MODE (x)) + & ~ GET_MODE_MASK (GET_MODE (SUBREG_REG (x)))); + } } break; |