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| author | Eric Botcazou <ebotcazou@adacore.com> | 2013-12-10 22:58:37 +0000 |
|---|---|---|
| committer | Eric Botcazou <ebotcazou@gcc.gnu.org> | 2013-12-10 22:58:37 +0000 |
| commit | 808c43038cdaaa1ad1a719a9027c8a5250a40c54 (patch) | |
| tree | b0155eff0eedb02194531ea371f532b7ed7f67d5 /gcc/simplify-rtx.c | |
| parent | 688974a346b1f73cbf94ebe0ca95f4690a7f922b (diff) | |
| download | gcc-808c43038cdaaa1ad1a719a9027c8a5250a40c54.tar.gz | |
re PR rtl-optimization/58295 (Missed zero-extension elimination in the combiner)
PR rtl-optimization/58295
* simplify-rtx.c (simplify_truncation): Restrict the distribution for
WORD_REGISTER_OPERATIONS targets.
From-SVN: r205874
Diffstat (limited to 'gcc/simplify-rtx.c')
| -rw-r--r-- | gcc/simplify-rtx.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c index ec138584c38..78cd665e9a8 100644 --- a/gcc/simplify-rtx.c +++ b/gcc/simplify-rtx.c @@ -640,11 +640,16 @@ simplify_truncation (enum machine_mode mode, rtx op, XEXP (op, 0), origmode); } - /* Simplify (truncate:SI (op:DI (x:DI) (y:DI))) - to (op:SI (truncate:SI (x:DI)) (truncate:SI (x:DI))). */ - if (GET_CODE (op) == PLUS - || GET_CODE (op) == MINUS - || GET_CODE (op) == MULT) + /* If the machine can perform operations in the truncated mode, distribute + the truncation, i.e. simplify (truncate:QI (op:SI (x:SI) (y:SI))) into + (op:QI (truncate:QI (x:SI)) (truncate:QI (y:SI))). */ + if (1 +#ifdef WORD_REGISTER_OPERATIONS + && precision >= BITS_PER_WORD +#endif + && (GET_CODE (op) == PLUS + || GET_CODE (op) == MINUS + || GET_CODE (op) == MULT)) { rtx op0 = simplify_gen_unary (TRUNCATE, mode, XEXP (op, 0), op_mode); if (op0) |