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| author | Alexandre Oliva <aoliva@redhat.com> | 2015-02-04 14:23:33 +0000 |
|---|---|---|
| committer | Alexandre Oliva <aoliva@gcc.gnu.org> | 2015-02-04 14:23:33 +0000 |
| commit | a720f0efffdf29c2f486e3d825446be4aa77b375 (patch) | |
| tree | 12c5c10d4bac82dd0e4f76d8300f90e15e0bab91 | |
| parent | a1ac80507d37425ef84fa68431bb2c63d6b27fef (diff) | |
| download | gcc-a720f0efffdf29c2f486e3d825446be4aa77b375.zip gcc-a720f0efffdf29c2f486e3d825446be4aa77b375.tar.gz gcc-a720f0efffdf29c2f486e3d825446be4aa77b375.tar.bz2 | |
Avoid allocating memory when trying but failing to simplify XOR of AND.
for gcc/ChangeLog
PR debug/64817
* simplify-rtx.c (simplify_binary_operation_1): Rewrite
simplification of XOR of AND to not allocate new rtx before
committing to a simplification.
From-SVN: r220404
| -rw-r--r-- | gcc/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/simplify-rtx.c | 29 |
2 files changed, 31 insertions, 5 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index d63c59c..685f4b8 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2015-02-04 Alexandre Oliva <aoliva@redhat.com> + + PR debug/64817 + * simplify-rtx.c (simplify_binary_operation_1): Rewrite + simplification of XOR of AND to not allocate new rtx before + committing to a simplification. + 2015-02-04 Kyrylo Tkachov <kyrylo.tkachov@arm.com> * config/aarch64/aarch64-ldpstp.md: Use std::swap instead of diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c index 5c9e3bf..bea9ec3 100644 --- a/gcc/simplify-rtx.c +++ b/gcc/simplify-rtx.c @@ -2724,12 +2724,31 @@ simplify_binary_operation_1 (enum rtx_code code, machine_mode mode, HOST_WIDE_INT bval = INTVAL (b); HOST_WIDE_INT cval = INTVAL (c); - rtx na_c - = simplify_binary_operation (AND, mode, - simplify_gen_unary (NOT, mode, a, mode), - c); + /* Instead of computing ~A&C, we compute its negated value, + ~(A|~C). If it yields -1, ~A&C is zero, so we can + optimize for sure. If it does not simplify, we still try + to compute ~A&C below, but since that always allocates + RTL, we don't try that before committing to returning a + simplified expression. */ + rtx n_na_c = simplify_binary_operation (IOR, mode, a, + GEN_INT (~cval)); + if ((~cval & bval) == 0) { + rtx na_c = NULL_RTX; + if (n_na_c) + na_c = simplify_gen_unary (NOT, mode, n_na_c, mode); + else + { + /* If ~A does not simplify, don't bother: we don't + want to simplify 2 operations into 3, and if na_c + were to simplify with na, n_na_c would have + simplified as well. */ + rtx na = simplify_unary_operation (NOT, mode, a, mode); + if (na) + na_c = simplify_gen_binary (AND, mode, na, c); + } + /* Try to simplify ~A&C | ~B&C. */ if (na_c != NULL_RTX) return simplify_gen_binary (IOR, mode, na_c, @@ -2738,7 +2757,7 @@ simplify_binary_operation_1 (enum rtx_code code, machine_mode mode, else { /* If ~A&C is zero, simplify A&(~C&B) | ~B&C. */ - if (na_c == const0_rtx) + if (n_na_c == CONSTM1_RTX (mode)) { rtx a_nc_b = simplify_gen_binary (AND, mode, a, gen_int_mode (~cval & bval, |