diff options
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/tree-ssa/vrp53.c | 24 | ||||
| -rw-r--r-- | gcc/tree-vrp.c | 92 |
4 files changed, 125 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 0b7b39e0353..0652932b5f9 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2010-07-12 Jakub Jelinek <jakub@redhat.com> + + * tree-vrp.c (simplify_bit_ops_using_ranges): New function. + (simplify_stmt_using_ranges): Use it. + 2010-07-12 Ulrich Weigand <Ulrich.Weigand@de.ibm.com> * config/spu/spu.h (struct spu_builtin_description): Remove FNDECL diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index f9870585d2b..94f7e77f928 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2010-07-12 Jakub Jelinek <jakub@redhat.com> + + * gcc.dg/tree-ssa/vrp53.c: New test. + 2010-07-12 Paolo Carlini <paolo.carlini@oracle.com> PR c++/44907 diff --git a/gcc/testsuite/gcc.dg/tree-ssa/vrp53.c b/gcc/testsuite/gcc.dg/tree-ssa/vrp53.c new file mode 100644 index 00000000000..66bbfb67b90 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/vrp53.c @@ -0,0 +1,24 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-vrp1" } */ + +int +f1 (int x) +{ + x &= 0xff; + x += 0x400; + x &= 0x7ff; + return x; +} + +int +f2 (int x) +{ + x &= 0xff; + x += 0x5400; + x |= 0x4400; + return x; +} + +/* { dg-final { scan-tree-dump-not "\& (2047|0x7ff)" "vrp1" } } */ +/* { dg-final { scan-tree-dump-not "\\| (17408|0x4400)" "vrp1" } } */ +/* { dg-final { cleanup-tree-dump "vrp1" } } */ diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index c8555110a59..afe69a3b8a1 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -6913,6 +6913,89 @@ simplify_abs_using_ranges (gimple stmt) return false; } +/* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR. + If all the bits that are being cleared by & are already + known to be zero from VR, or all the bits that are being + set by | are already known to be one from VR, the bit + operation is redundant. */ + +static bool +simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt) +{ + tree op0 = gimple_assign_rhs1 (stmt); + tree op1 = gimple_assign_rhs2 (stmt); + tree op = NULL_TREE; + value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL }; + value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL }; + double_int may_be_nonzero0, may_be_nonzero1; + double_int must_be_nonzero0, must_be_nonzero1; + double_int mask; + + if (TREE_CODE (op0) == SSA_NAME) + vr0 = *(get_value_range (op0)); + else if (is_gimple_min_invariant (op0)) + set_value_range_to_value (&vr0, op0, NULL); + else + return false; + + if (TREE_CODE (op1) == SSA_NAME) + vr1 = *(get_value_range (op1)); + else if (is_gimple_min_invariant (op1)) + set_value_range_to_value (&vr1, op1, NULL); + else + return false; + + if (!zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0, &must_be_nonzero0)) + return false; + if (!zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1, &must_be_nonzero1)) + return false; + + switch (gimple_assign_rhs_code (stmt)) + { + case BIT_AND_EXPR: + mask = double_int_and (may_be_nonzero0, + double_int_not (must_be_nonzero1)); + if (double_int_zero_p (mask)) + { + op = op0; + break; + } + mask = double_int_and (may_be_nonzero1, + double_int_not (must_be_nonzero0)); + if (double_int_zero_p (mask)) + { + op = op1; + break; + } + break; + case BIT_IOR_EXPR: + mask = double_int_and (may_be_nonzero0, + double_int_not (must_be_nonzero1)); + if (double_int_zero_p (mask)) + { + op = op1; + break; + } + mask = double_int_and (may_be_nonzero1, + double_int_not (must_be_nonzero0)); + if (double_int_zero_p (mask)) + { + op = op0; + break; + } + break; + default: + gcc_unreachable (); + } + + if (op == NULL_TREE) + return false; + + gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op, NULL); + update_stmt (gsi_stmt (*gsi)); + return true; +} + /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has a known value range VR. @@ -7198,6 +7281,15 @@ simplify_stmt_using_ranges (gimple_stmt_iterator *gsi) return simplify_abs_using_ranges (stmt); break; + case BIT_AND_EXPR: + case BIT_IOR_EXPR: + /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR + if all the bits being cleared are already cleared or + all the bits being set are already set. */ + if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))) + return simplify_bit_ops_using_ranges (gsi, stmt); + break; + default: break; } |