| Message ID | 20140110204522.GI892@tucnak.redhat.com |
|---|---|
| State | New |
| Headers | show |
On 01/10/14 13:45, Jakub Jelinek wrote: > Hi! > > The new REGNO != REGNO optimization assumes that a lowpart subreg of > the extended reg will be the value of the original expression. > But that is the case of only scalar integral modes, e.g. for vector > mode extensions a lowpart subreg will occupy just say half or even fewer > vector elements, but in the extended element values instead of original. > > Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, > and eyeballed the testcase for AVX512F from the testsuite. Ok for trunk? > > 2014-01-10 Jakub Jelinek <jakub@redhat.com> > > PR rtl-optimization/59754 > * ree.c (combine_reaching_defs): Disallow !SCALAR_INT_MODE_P > modes in the REGNO != REGNO case. Yes, this is fine. Thanks for taking care of it, my testing boxes are busy testing the other two queued ree things. jeff
--- gcc/ree.c.jj 2014-01-09 08:19:39.000000000 +0100 +++ gcc/ree.c 2014-01-10 13:51:14.216730694 +0100 @@ -702,6 +702,18 @@ combine_reaching_defs (ext_cand *cand, c if (state->modified[INSN_UID (cand->insn)].kind != EXT_MODIFIED_NONE) return false; + /* Transformation of + (set (reg1) (expression)) + (set (reg2) (any_extend (reg1))) + into + (set (reg2) (any_extend (expression))) + (set (reg1) (reg2)) + is only valid for scalar integral modes, as it relies on the low + subreg of reg1 to have the value of (expression), which is not true + e.g. for vector modes. */ + if (!SCALAR_INT_MODE_P (GET_MODE (SET_DEST (PATTERN (cand->insn))))) + return false; + /* There's only one reaching def. */ rtx def_insn = state->defs_list[0];