This fixes (ISTR we've been here before) slpeel_duplicate_current_defs_from_edges being dependent on PHI node ordering which can be disrupted by SSA update inserting virtual PHIs.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied. Richard. 2016-08-19 Richard Biener <rguent...@suse.de> PR tree-optimization/77286 * tree-vect-loop-manip.c (slpeel_duplicate_current_defs_from_edges): Deal with virtual PHIs being out-of-order. * gcc.dg/torture/pr77286.c: New testcase. Index: gcc/tree-vect-loop-manip.c =================================================================== --- gcc/tree-vect-loop-manip.c (revision 239567) +++ gcc/tree-vect-loop-manip.c (working copy) @@ -735,22 +735,33 @@ slpeel_duplicate_current_defs_from_edges gimple *from_phi = gsi_stmt (gsi_from); gimple *to_phi = gsi_stmt (gsi_to); tree from_arg = PHI_ARG_DEF_FROM_EDGE (from_phi, from); - if (TREE_CODE (from_arg) != SSA_NAME) - { + tree to_arg = PHI_ARG_DEF_FROM_EDGE (to_phi, to); + if (virtual_operand_p (from_arg)) + { gsi_next (&gsi_from); continue; } - tree to_arg = PHI_ARG_DEF_FROM_EDGE (to_phi, to); - if (TREE_CODE (to_arg) != SSA_NAME) - { + if (virtual_operand_p (to_arg)) + { gsi_next (&gsi_to); continue; } - if (get_current_def (to_arg) == NULL_TREE) - set_current_def (to_arg, get_current_def (from_arg)); + if (TREE_CODE (from_arg) != SSA_NAME) + gcc_assert (operand_equal_p (from_arg, to_arg, 0)); + else + { + if (get_current_def (to_arg) == NULL_TREE) + set_current_def (to_arg, get_current_def (from_arg)); + } gsi_next (&gsi_from); gsi_next (&gsi_to); } + + gphi *from_phi = get_virtual_phi (from->dest); + gphi *to_phi = get_virtual_phi (to->dest); + if (from_phi) + set_current_def (PHI_ARG_DEF_FROM_EDGE (to_phi, to), + get_current_def (PHI_ARG_DEF_FROM_EDGE (from_phi, from))); } Index: gcc/testsuite/gcc.dg/torture/pr77286.c =================================================================== --- gcc/testsuite/gcc.dg/torture/pr77286.c (revision 0) +++ gcc/testsuite/gcc.dg/torture/pr77286.c (working copy) @@ -0,0 +1,43 @@ +/* { dg-do compile } */ +/* { dg-additional-options "-mavx2" { target x86_64-*-* i?86-*-* } } */ + +typedef float real; +typedef struct +{ + int ngtc; + real *ref_t; + real *tau_t; +} t_grpopts; +typedef struct +{ + real T; + real xi; +} t_grp_tcstat; +typedef struct +{ + t_grp_tcstat *tcstat; +} t_groups; +extern real *save_calloc (); +void +nosehoover_tcoupl (t_grpopts * opts, t_groups * grps, real dt, real SAfactor) +{ + static real *Qinv = ((void *) 0); + int i; + real reft = 0, xit, oldxi; + if (Qinv == ((void *) 0)) + { + (Qinv) = + save_calloc ("Qinv", "coupling.c", 372, (opts->ngtc), + sizeof (*(Qinv))); + for (i = 0; i < opts->ngtc; i++) + if ((opts->tau_t[i] > 0)) + Qinv[i] = 1.0 / opts->tau_t[i]; + } + for (i = 0; (i < opts->ngtc); i++) + { + reft = + (((0.0) > + (opts->ref_t[i] * SAfactor)) ? (0.0) : (opts->ref_t[i] * SAfactor)); + grps->tcstat[i].xi += dt * Qinv[i] * (grps->tcstat[i].T - reft); + } +}