diff options
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index c605b1a..f772878 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -104,10 +104,6 @@ along with GCC; see the file COPYING3. If not see #include "rtl-iter.h" #include "print-rtl.h" -#ifndef LOAD_EXTEND_OP -#define LOAD_EXTEND_OP(M) UNKNOWN -#endif - /* Number of attempts to combine instructions in this function. */ static int combine_attempts; @@ -12465,14 +12461,14 @@ simplify_comparison (enum rtx_code code, rtx *pop0, rtx *pop1) care bits and we can assume they have any convenient value. So making the transformation is safe. - 2. SUBREG_REG (op0) is a memory and LOAD_EXTEND_OP is not defined. + 2. SUBREG_REG (op0) is a memory and LOAD_EXTEND_OP is UNKNOWN. In this case the upper bits of op0 are undefined. We should not make the simplification in that case as we do not know the contents of those bits. - 3. SUBREG_REG (op0) is a memory and LOAD_EXTEND_OP is defined and not - UNKNOWN. In that case we know those bits are zeros or ones. We must - also be sure that they are the same as the upper bits of op1. + 3. SUBREG_REG (op0) is a memory and LOAD_EXTEND_OP is not UNKNOWN. + In that case we know those bits are zeros or ones. We must also be + sure that they are the same as the upper bits of op1. We can never remove a SUBREG for a non-equality comparison because the sign bit is in a different place in the underlying object. */ |