From: Jakub Jelinek Date: Fri, 1 Dec 2023 09:55:49 +0000 (+0100) Subject: lower-bitint: Fix up handle_operand_addr for 0 constants [PR112771] X-Git-Tag: basepoints/gcc-15~4089 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9bfebcb1b7ae4e7160644f2104424d6bab4a23f7;p=thirdparty%2Fgcc.git lower-bitint: Fix up handle_operand_addr for 0 constants [PR112771] handle_operand_addr for INTEGER_CSTs uses wi::min_precision (UNSIGNED for non-negative constants, SIGNED for negative ones) and from that computes mp as minimum number of limbs which can represent that value, and in some cases creates a test BITINT_TYPE with that precision to categorize it and decide based on that what types to use on the constant emitted into memory. For the actual precisions (what will be passed to libgcc) it actually already uses MAX/MIN to adjust the corner cases: *prec = MAX (min_prec, 1); ... *prec = MIN ((int) -min_prec, -2); but for integer_zerop min_prec will be 0, mp = CEIL (min_prec, limb_prec) * limb_prec; will be also 0 and we ICE trying to build unsigned BITINT_TYPE with 0 precision. Fixed thusly by noting even 0 has to be encoded at least as one limb. 2023-12-01 Jakub Jelinek PR middle-end/112771 * gimple-lower-bitint.cc (bitint_large_huge::handle_operand_addr): Use mp = 1 if it is zero. * gcc.dg/bitint-44.c: New test. --- diff --git a/gcc/gimple-lower-bitint.cc b/gcc/gimple-lower-bitint.cc index 7c8c640ab218..d0e24cbb6219 100644 --- a/gcc/gimple-lower-bitint.cc +++ b/gcc/gimple-lower-bitint.cc @@ -2179,6 +2179,8 @@ bitint_large_huge::handle_operand_addr (tree op, gimple *stmt, *prec = MIN ((int) -min_prec, -2); } mp = CEIL (min_prec, limb_prec) * limb_prec; + if (mp == 0) + mp = 1; if (mp >= (unsigned) TYPE_PRECISION (TREE_TYPE (op))) type = TREE_TYPE (op); else diff --git a/gcc/testsuite/gcc.dg/bitint-44.c b/gcc/testsuite/gcc.dg/bitint-44.c new file mode 100644 index 000000000000..d1f34d029612 --- /dev/null +++ b/gcc/testsuite/gcc.dg/bitint-44.c @@ -0,0 +1,10 @@ +/* PR middle-end/112771 */ +/* { dg-do compile { target bitint575 } } */ +/* { dg-options "-std=c23" } */ + +_BitInt(575) +foo (_BitInt(575) a) +{ + a /= 0; /* { dg-warning "division by zero" } */ + return a; +}