| Message ID | 3018517.UiVXHDucIc@polaris |
|---|---|
| State | New |
| Headers | show |
| Series | Fix PR tree-optimization/86514 | expand |
On Mon, Jul 16, 2018 at 9:52 AM Eric Botcazou <ebotcazou@adacore.com> wrote: > > Hi, > > this is a regression present on the mainline and 8 branch in the form of wrong > code generated for an Ada program manipulating bit-packed boolean array types. > > The problem is in the new range optimization code of the reassoc pass: from > > _64 = _63 | 4; > _73 = _64 & 191; > _76 = _64 >> 6; > _77 = (boolean) _76; > _78 = (boolean) _64; > _79 = _77 | _78; > > it deduces: > > Optimizing range tests _76 +[0, 0] and _64 +[0, 0] > |...] > _64 = _63 | 4; > _73 = _64 & 191; > _76 = _64 >> 6; > _90 = _76 | _64; > _19 = _90 != 0; > _77 = (boolean) _76; > _78 = (boolean) _64; > _79 = _19; > > which is not equivalent. The proposed fix is to avoid bypassing a conversion > to a boolean type from a type with greater precision in init_range_entry. > > Tested on x86_64-suse-linux, OK for the mainline? OK for trunk and branch. Thanks, Richard. > > 2018-07-16 Eric Botcazou <ebotcazou@adacore.com> > > PR tree-optimization/86514 > * tree-ssa-reassoc.c (init_range_entry) <CASE_CONVERT>: Return for a > conversion to a boolean type from a type with greater precision. > > > 2018-07-16 Eric Botcazou <ebotcazou@adacore.com> > > * gnat.dg/opt73.adb: New test. > > -- > Eric Botcazou
Index: tree-ssa-reassoc.c =================================================================== --- tree-ssa-reassoc.c (revision 262658) +++ tree-ssa-reassoc.c (working copy) @@ -2168,8 +2168,13 @@ init_range_entry (struct range_entry *r, continue; CASE_CONVERT: if (is_bool) - goto do_default; - if (TYPE_PRECISION (TREE_TYPE (arg0)) == 1) + { + if ((TYPE_PRECISION (exp_type) == 1 + || TREE_CODE (exp_type) == BOOLEAN_TYPE) + && TYPE_PRECISION (TREE_TYPE (arg0)) > 1) + return; + } + else if (TYPE_PRECISION (TREE_TYPE (arg0)) == 1) { if (TYPE_UNSIGNED (TREE_TYPE (arg0))) is_bool = true;