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From: Richard Biener <rguenth@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc r12-3071] tree-optimization/79334 - avoid PRE of possibly trapping array-ref Date: Mon, 23 Aug 2021 09:53:30 +0000 (GMT) [thread overview] Message-ID: <20210823095330.879F4385842C@sourceware.org> (raw) https://gcc.gnu.org/g:ad665deeafd31238b537139385e1e80b40c10e0c commit r12-3071-gad665deeafd31238b537139385e1e80b40c10e0c Author: Richard Biener <rguenther@suse.de> Date: Mon Aug 23 09:57:05 2021 +0200 tree-optimization/79334 - avoid PRE of possibly trapping array-ref This replicates tree-eh.c in_array_bound_p into VNs vn_reference_may_trap to fix hoisting of a possibly trapping ARRAY_REF across a call that might not return. 2021-08-23 Richard Biener <rguenther@suse.de> PR tree-optimization/79334 * tree-ssa-sccvn.c (copy_reference_ops_from_ref): Record a type also for COMPONENT_REFs. (vn_reference_may_trap): Check ARRAY_REF with constant index against the array domain. * gcc.dg/torture/pr79334-0.c: New testcase. * gcc.dg/torture/pr79334-1.c: Likewise. Diff: --- gcc/testsuite/gcc.dg/torture/pr79334-0.c | 23 +++++++++++++++++++++++ gcc/testsuite/gcc.dg/torture/pr79334-1.c | 1 + gcc/tree-ssa-sccvn.c | 30 ++++++++++++++++++++++++++---- 3 files changed, 50 insertions(+), 4 deletions(-) diff --git a/gcc/testsuite/gcc.dg/torture/pr79334-0.c b/gcc/testsuite/gcc.dg/torture/pr79334-0.c new file mode 100644 index 00000000000..fa45a6d77d0 --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr79334-0.c @@ -0,0 +1,23 @@ +/* { dg-do run } */ +/* { dg-additional-sources "pr79334-1.c" } */ + +extern int d[][8]; + +static void __attribute__((noinline)) +func_that_exits (int flag) +{ + if (!flag) + __builtin_exit (0); +} + +int main () +{ + int e = 0; + while (1) + { + func_that_exits (e); + /* We do not know whether d[1024][0] will trap. */ + e = d[1024][0]; + } + return 0; +} diff --git a/gcc/testsuite/gcc.dg/torture/pr79334-1.c b/gcc/testsuite/gcc.dg/torture/pr79334-1.c new file mode 100644 index 00000000000..b1c8a27753e --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr79334-1.c @@ -0,0 +1 @@ +int d[1][8]; diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c index 82bd10bd83c..bf87cee3857 100644 --- a/gcc/tree-ssa-sccvn.c +++ b/gcc/tree-ssa-sccvn.c @@ -914,9 +914,8 @@ copy_reference_ops_from_ref (tree ref, vec<vn_reference_op_s> *result) break; case COMPONENT_REF: /* The field decl is enough to unambiguously specify the field, - a matching type is not necessary and a mismatching type - is always a spurious difference. */ - temp.type = NULL_TREE; + so use its type here. */ + temp.type = TREE_TYPE (TREE_OPERAND (ref, 1)); temp.op0 = TREE_OPERAND (ref, 1); temp.op1 = TREE_OPERAND (ref, 2); temp.reverse = (AGGREGATE_TYPE_P (TREE_TYPE (TREE_OPERAND (ref, 0))) @@ -5873,10 +5872,33 @@ vn_reference_may_trap (vn_reference_t ref) return true; break; case ARRAY_RANGE_REF: - case ARRAY_REF: if (TREE_CODE (op->op0) == SSA_NAME) return true; break; + case ARRAY_REF: + { + if (TREE_CODE (op->op0) != INTEGER_CST) + return true; + + /* !in_array_bounds */ + tree domain_type = TYPE_DOMAIN (ref->operands[i+1].type); + if (!domain_type) + return true; + + tree min = op->op1; + tree max = TYPE_MAX_VALUE (domain_type); + if (!min + || !max + || TREE_CODE (min) != INTEGER_CST + || TREE_CODE (max) != INTEGER_CST) + return true; + + if (tree_int_cst_lt (op->op0, min) + || tree_int_cst_lt (max, op->op0)) + return true; + + break; + } case MEM_REF: /* Nothing interesting in itself, the base is separate. */ break;
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