Hi!
SMS is done before reload and assumes it can extend the lifetime by making
copies of the destination registers without trying to re-recognize the
instructions etc. That can work only with pseudos, for some hard registers
there isn't even a valid move instruction to pseudo (e.g. the powerpc CA
register), for others it can be very much undesirable.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2018-01-09 Jakub Jelinek <ja...@redhat.com>
PR target/83507
* modulo-sched.c (schedule_reg_moves): Punt if we'd need to move
hard registers. Formatting fixes.
* gcc.dg/sms-13.c: New test.
--- gcc/modulo-sched.c.jj 2018-01-03 10:19:55.710534046 +0100
+++ gcc/modulo-sched.c 2018-01-08 16:53:01.232465389 +0100
@@ -687,9 +687,9 @@ schedule_reg_moves (partial_schedule_ptr
rtx set = single_set (u->insn);
/* Skip instructions that do not set a register. */
- if ((set && !REG_P (SET_DEST (set))))
+ if (set && !REG_P (SET_DEST (set)))
continue;
-
+
/* Compute the number of reg_moves needed for u, by looking at life
ranges started at u (excluding self-loops). */
distances[0] = distances[1] = false;
@@ -743,7 +743,10 @@ schedule_reg_moves (partial_schedule_ptr
first_move += ps->g->num_nodes;
/* Generate each move. */
- old_reg = prev_reg = SET_DEST (single_set (u->insn));
+ old_reg = prev_reg = SET_DEST (set);
+ if (HARD_REGISTER_P (old_reg))
+ return false;
+
for (i_reg_move = 0; i_reg_move < nreg_moves; i_reg_move++)
{
ps_reg_move_info *move = ps_reg_move (ps, first_move + i_reg_move);
--- gcc/testsuite/gcc.dg/sms-13.c.jj 2018-01-08 17:00:16.427534076 +0100
+++ gcc/testsuite/gcc.dg/sms-13.c 2018-01-08 16:56:15.704496101 +0100
@@ -0,0 +1,32 @@
+/* PR target/83507 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fmodulo-sched -fno-tree-ter -fno-tree-coalesce-vars" } */
+
+void
+foo (unsigned short int x, unsigned char y)
+{
+ unsigned char *a = &y;
+ unsigned short int b;
+ int c;
+
+ while (y < 3)
+ {
+ if (x != 0)
+ ++y;
+ ++y;
+ }
+
+ for (c = 0; c < 5; ++c)
+ {
+ int d = 1;
+ d += b > x;
+ y &= d;
+ }
+
+ do
+ {
+ c += y;
+ x = c;
+ }
+ while (x != 0);
+}
Jakub
