Hi! Since r10-6527-gaaa26bf496a646778ac861aed124d960b5bf549f fold_for_warn will perform maybe_constant_value even on some cp_fold produced trees and so can include rotate exprs which were removed last fall from constexpr.c
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 2020-03-06 Jakub Jelinek <ja...@redhat.com> PR c++/94067 Revert 2019-10-11 Paolo Carlini <paolo.carl...@oracle.com> * constexpr.c (cxx_eval_constant_expression): Do not handle RROTATE_EXPR and LROTATE_EXPR. * g++.dg/warn/Wconversion-pr94067.C: New test. --- gcc/cp/constexpr.c.jj 2020-03-05 07:58:02.578137680 +0100 +++ gcc/cp/constexpr.c 2020-03-06 11:55:27.126682726 +0100 @@ -5730,6 +5730,8 @@ cxx_eval_constant_expression (const cons case MAX_EXPR: case LSHIFT_EXPR: case RSHIFT_EXPR: + case LROTATE_EXPR: + case RROTATE_EXPR: case BIT_IOR_EXPR: case BIT_XOR_EXPR: case BIT_AND_EXPR: @@ -7853,6 +7855,8 @@ potential_constant_expression_1 (tree t, case MAX_EXPR: case LSHIFT_EXPR: case RSHIFT_EXPR: + case LROTATE_EXPR: + case RROTATE_EXPR: case BIT_IOR_EXPR: case BIT_XOR_EXPR: case BIT_AND_EXPR: --- gcc/testsuite/g++.dg/warn/Wconversion-pr94067.C.jj 2020-03-06 11:57:08.335191087 +0100 +++ gcc/testsuite/g++.dg/warn/Wconversion-pr94067.C 2020-03-06 11:59:55.843722307 +0100 @@ -0,0 +1,9 @@ +// PR c++/94067 +// { dg-do compile } +// { dg-options "-Wconversion" } + +static inline unsigned short +swap (unsigned short x) +{ + return (x >> 8) | static_cast<unsigned short>(x << 8); +} Jakub