From 8c1f1d428facaaa17c3ce21cfef418948e3c52fa Mon Sep 17 00:00:00 2001 From: Richard Guenther Date: Tue, 15 May 2012 13:18:32 +0000 Subject: [PATCH] re PR tree-optimization/53355 (Autovectorization of a simple loop could be improved.) 2012-05-15 Richard Guenther PR tree-optimization/53355 * tree-vrp.c (extract_range_from_binary_expr_1): Handle LSHIFT_EXPRs by constants. * gcc.dg/tree-ssa/vrp67.c: New testcase. From-SVN: r187535 --- gcc/ChangeLog | 6 +++++ gcc/testsuite/ChangeLog | 5 ++++ gcc/testsuite/gcc.dg/tree-ssa/vrp67.c | 38 +++++++++++++++++++++++++++ gcc/tree-vrp.c | 35 ++++++++++++++++++++++++ 4 files changed, 84 insertions(+) create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/vrp67.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 180e62c9591..c1e22974f43 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2012-05-15 Richard Guenther + + PR tree-optimization/53355 + * tree-vrp.c (extract_range_from_binary_expr_1): Handle LSHIFT_EXPRs + by constants. + 2012-05-15 Tristan Gingold * tree-ssa-strlen.c (get_string_length): Convert lhs if needed. diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 9980ad7e294..8e82b012b03 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2012-05-15 Richard Guenther + + PR tree-optimization/53355 + * gcc.dg/tree-ssa/vrp67.c: New testcase. + 2012-05-15 Bernhard Reutner-Fischer * gfortran.dg/*.f90: Remove now redundant manual diff --git a/gcc/testsuite/gcc.dg/tree-ssa/vrp67.c b/gcc/testsuite/gcc.dg/tree-ssa/vrp67.c new file mode 100644 index 00000000000..f02d83780a6 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/vrp67.c @@ -0,0 +1,38 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-vrp1" } */ + +unsigned foo (unsigned i) +{ + if (i == 2) + { + i = i << 2; + if (i != 8) + link_error (); + } + return i; +} +unsigned bar (unsigned i) +{ + if (i == 1 << (sizeof (unsigned) * 8 - 1)) + { + i = i << 1; + if (i != 0) + link_error (); + } + return i; +} +unsigned baz (unsigned i) +{ + i = i & 15; + if (i == 0) + return 0; + i = 1000 - i; + i >>= 1; + i <<= 1; + if (i == 0) + link_error (); + return i; +} + +/* { dg-final { scan-tree-dump-times "Folding predicate" 3 "vrp1" } } */ +/* { dg-final { cleanup-tree-dump "vrp1" } } */ diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index 72c647fca4a..4dc942cc388 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -2403,6 +2403,7 @@ extract_range_from_binary_expr_1 (value_range_t *vr, && code != ROUND_DIV_EXPR && code != TRUNC_MOD_EXPR && code != RSHIFT_EXPR + && code != LSHIFT_EXPR && code != MIN_EXPR && code != MAX_EXPR && code != BIT_AND_EXPR @@ -2596,6 +2597,40 @@ extract_range_from_binary_expr_1 (value_range_t *vr, extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1); return; } + else if (code == LSHIFT_EXPR) + { + /* If we have a LSHIFT_EXPR with any shift values outside [0..prec-1], + then drop to VR_VARYING. Outside of this range we get undefined + behavior from the shift operation. We cannot even trust + SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl + shifts, and the operation at the tree level may be widened. */ + if (vr1.type != VR_RANGE + || !value_range_nonnegative_p (&vr1) + || TREE_CODE (vr1.max) != INTEGER_CST + || compare_tree_int (vr1.max, TYPE_PRECISION (expr_type) - 1) == 1) + { + set_value_range_to_varying (vr); + return; + } + + /* We can map shifts by constants to MULT_EXPR handling. */ + if (range_int_cst_singleton_p (&vr1)) + { + value_range_t vr1p = { VR_RANGE, NULL_TREE, NULL_TREE, NULL }; + vr1p.min + = double_int_to_tree (expr_type, + double_int_lshift (double_int_one, + TREE_INT_CST_LOW (vr1.min), + TYPE_PRECISION (expr_type), + false)); + vr1p.max = vr1p.min; + extract_range_from_multiplicative_op_1 (vr, MULT_EXPR, &vr0, &vr1p); + return; + } + + set_value_range_to_varying (vr); + return; + } else if (code == TRUNC_DIV_EXPR || code == FLOOR_DIV_EXPR || code == CEIL_DIV_EXPR -- 2.30.2