From fe19699ae2883b252d30f98481d32dabff00744b Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Thu, 5 Mar 2020 08:00:04 +0100 Subject: sccvn: Fix handling of POINTER_PLUS_EXPR in memset offset [PR93582] > > where POINTER_PLUS_EXPR last operand has sizetype type, thus unsigned, > > and in the testcase gimple_assign_rhs2 (def) is thus 0xf000000000000001ULL > > which multiplied by 8 doesn't fit into signed HWI. If it would be treated > > as signed offset instead, it would fit (-0xfffffffffffffffLL, multiplied > > by 8 is -0x7ffffffffffffff8LL). Unfortunately with the poly_int obfuscation > > I'm not sure how to convert it from unsigned to signed poly_int. > > mem_ref_offset provides a boiler-plate for this: > > poly_offset_int::from (wi::to_poly_wide (TREE_OPERAND (t, 1)), SIGNED); Thanks, that seems to work. The test now works on both big-endian and little-endian. 2020-03-05 Richard Biener Jakub Jelinek PR tree-optimization/93582 * tree-ssa-sccvn.c (vn_reference_lookup_3): Treat POINTER_PLUS_EXPR last operand as signed when looking for memset offset. Formatting fix. * gcc.dg/tree-ssa/pr93582-11.c: New test. Co-authored-by: Richard Biener --- gcc/tree-ssa-sccvn.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'gcc/tree-ssa-sccvn.c') diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c index 9ea30ef..b7174cd 100644 --- a/gcc/tree-ssa-sccvn.c +++ b/gcc/tree-ssa-sccvn.c @@ -2656,7 +2656,8 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_, { poly_int64 soff; if (TREE_CODE (base) != MEM_REF - || !(mem_ref_offset (base) << LOG2_BITS_PER_UNIT).to_shwi (&soff)) + || !(mem_ref_offset (base) + << LOG2_BITS_PER_UNIT).to_shwi (&soff)) return (void *)-1; offset += soff; offset2 = 0; @@ -2666,10 +2667,13 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_, if (is_gimple_assign (def) && gimple_assign_rhs_code (def) == POINTER_PLUS_EXPR && gimple_assign_rhs1 (def) == TREE_OPERAND (base, 0) - && poly_int_tree_p (gimple_assign_rhs2 (def)) - && (wi::to_poly_offset (gimple_assign_rhs2 (def)) - << LOG2_BITS_PER_UNIT).to_shwi (&offset2)) + && poly_int_tree_p (gimple_assign_rhs2 (def))) { + tree rhs2 = gimple_assign_rhs2 (def); + if (!(poly_offset_int::from (wi::to_poly_wide (rhs2), + SIGNED) + << LOG2_BITS_PER_UNIT).to_shwi (&offset2)) + return (void *)-1; ref2 = gimple_assign_rhs1 (def); if (TREE_CODE (ref2) == SSA_NAME) ref2 = SSA_VAL (ref2); -- cgit v1.1