From d902a1b57606536982a1001670f998de685eaf7c Mon Sep 17 00:00:00 2001 From: Aldy Hernandez Date: Wed, 12 May 2021 15:22:15 -0400 Subject: [PATCH] Skip out on processing __builtin_clz when varying. The previous changes to irange::constant_p return TRUE for VARYING, since VARYING has numerical end points like any other constant range. The problem is that some users of constant_p depended on constant_p excluding the full domain. The range handler for __builtin_clz, that is shared between ranger and vr_values, is one such user. This patch excludes varying_p(), to match the original behavior for clz. gcc/ChangeLog: PR c/100521 * gimple-range.cc (range_of_builtin_call): Skip out on processing __builtin_clz when varying. --- gcc/gimple-range.cc | 2 +- gcc/testsuite/gcc.dg/pr100521.c | 8 ++++++++ 2 files changed, 9 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.dg/pr100521.c diff --git a/gcc/gimple-range.cc b/gcc/gimple-range.cc index e94bb35..5b288d8 100644 --- a/gcc/gimple-range.cc +++ b/gcc/gimple-range.cc @@ -737,7 +737,7 @@ range_of_builtin_call (range_query &query, irange &r, gcall *call) query.range_of_expr (r, arg, call); // From clz of minimum we can compute result maximum. - if (r.constant_p ()) + if (r.constant_p () && !r.varying_p ()) { int newmaxi = prec - 1 - wi::floor_log2 (r.lower_bound ()); // Argument is unsigned, so do nothing if it is [0, ...] range. diff --git a/gcc/testsuite/gcc.dg/pr100521.c b/gcc/testsuite/gcc.dg/pr100521.c new file mode 100644 index 0000000..fd9f0db --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr100521.c @@ -0,0 +1,8 @@ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ + +int +__builtin_clz (int a) +{ + return __builtin_clz(a); +} -- 2.7.4