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From: Jakub Jelinek <jakub@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc r12-6135] fold-const: Fix up fold_truth_andor_1 shift handling [PR103813] Date: Tue, 28 Dec 2021 16:41:54 +0000 (GMT) [thread overview] Message-ID: <20211228164154.9CDD33858C60@sourceware.org> (raw) https://gcc.gnu.org/g:9258ac53cfcbe546e8b86a433e59343538743f74 commit r12-6135-g9258ac53cfcbe546e8b86a433e59343538743f74 Author: Jakub Jelinek <jakub@redhat.com> Date: Tue Dec 28 17:41:24 2021 +0100 fold-const: Fix up fold_truth_andor_1 shift handling [PR103813] Some time ago I've changed const_binop -> wide_int_binop, so that it punts on shifts by negative count. fold_truth_andor_1 doesn't check the results of const_binop (?SHIFT_EXPR, ) though and assumes they will be always non-NULL, which is no longer the case. 2021-12-28 Jakub Jelinek <jakub@redhat.com> PR middle-end/103813 * fold-const.c (fold_truth_andor_1): Punt of const_binop LSHIFT_EXPR or RSHIFT_EXPR returns NULL. Formatting fix. * gcc.c-torture/compile/pr103813.c: New test. Diff: --- gcc/fold-const.c | 14 ++++++++++++-- gcc/testsuite/gcc.c-torture/compile/pr103813.c | 10 ++++++++++ 2 files changed, 22 insertions(+), 2 deletions(-) diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 0b9a42f764a..14aa9ca659b 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -6454,15 +6454,19 @@ fold_truth_andor_1 (location_t loc, enum tree_code code, tree truth_type, size_int (xll_bitpos)); rl_mask = const_binop (LSHIFT_EXPR, fold_convert_loc (loc, lntype, rl_mask), size_int (xrl_bitpos)); + if (ll_mask == NULL_TREE || rl_mask == NULL_TREE) + return 0; if (l_const) { l_const = fold_convert_loc (loc, lntype, l_const); l_const = unextend (l_const, ll_bitsize, ll_unsignedp, ll_and_mask); l_const = const_binop (LSHIFT_EXPR, l_const, size_int (xll_bitpos)); + if (l_const == NULL_TREE) + return 0; if (! integer_zerop (const_binop (BIT_AND_EXPR, l_const, fold_build1_loc (loc, BIT_NOT_EXPR, - lntype, ll_mask)))) + lntype, ll_mask)))) { warning (0, "comparison is always %d", wanted_code == NE_EXPR); @@ -6474,9 +6478,11 @@ fold_truth_andor_1 (location_t loc, enum tree_code code, tree truth_type, r_const = fold_convert_loc (loc, lntype, r_const); r_const = unextend (r_const, rl_bitsize, rl_unsignedp, rl_and_mask); r_const = const_binop (LSHIFT_EXPR, r_const, size_int (xrl_bitpos)); + if (r_const == NULL_TREE) + return 0; if (! integer_zerop (const_binop (BIT_AND_EXPR, r_const, fold_build1_loc (loc, BIT_NOT_EXPR, - lntype, rl_mask)))) + lntype, rl_mask)))) { warning (0, "comparison is always %d", wanted_code == NE_EXPR); @@ -6521,6 +6527,8 @@ fold_truth_andor_1 (location_t loc, enum tree_code code, tree truth_type, rr_mask = const_binop (LSHIFT_EXPR, fold_convert_loc (loc, rntype, rr_mask), size_int (xrr_bitpos)); + if (lr_mask == NULL_TREE || rr_mask == NULL_TREE) + return 0; /* Make a mask that corresponds to both fields being compared. Do this for both items being compared. If the operands are the @@ -6580,6 +6588,8 @@ fold_truth_andor_1 (location_t loc, enum tree_code code, tree truth_type, size_int (MIN (xll_bitpos, xrl_bitpos))); lr_mask = const_binop (RSHIFT_EXPR, lr_mask, size_int (MIN (xlr_bitpos, xrr_bitpos))); + if (ll_mask == NULL_TREE || lr_mask == NULL_TREE) + return 0; /* Convert to the smaller type before masking out unwanted bits. */ type = lntype; diff --git a/gcc/testsuite/gcc.c-torture/compile/pr103813.c b/gcc/testsuite/gcc.c-torture/compile/pr103813.c new file mode 100644 index 00000000000..b3fc066beed --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/compile/pr103813.c @@ -0,0 +1,10 @@ +/* PR middle-end/103813 */ + +struct A { char b; char c[0x21000000]; }; +struct A d; + +int +foo () +{ + return d.c[0x20000000] || d.c[1]; +}
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