[Bug target/70465] [5/6 Regression] Poor code for x87 asm

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70465

--- Comment #17 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
So:
--- gcc/reg-stack.c.jj  2017-01-26 09:46:03.000000000 +0100
+++ gcc/reg-stack.c     2017-02-21 16:10:28.969463832 +0100
@@ -897,10 +897,13 @@ emit_swap_insn (rtx_insn *insn, stack_pt
           fld a
          if possible.  */

+      i1src = SET_SRC (i1set);
+      if (GET_CODE (i1src) == FLOAT_EXTEND)
+       i1src = XEXP (i1src, 0);
       if (REG_P (i1dest)
          && REGNO (i1dest) == FIRST_STACK_REG
-         && MEM_P (SET_SRC (i1set))
-         && !side_effects_p (SET_SRC (i1set))
+         && MEM_P (i1src)
+         && !side_effects_p (i1src)
          && hard_regno == FIRST_STACK_REG + 1
          && i1 != BB_HEAD (current_block))
        {
@@ -930,6 +933,9 @@ emit_swap_insn (rtx_insn *insn, stack_pt
              && (i2set = single_set (i2)) != NULL_RTX)
            {
              rtx i2dest = *get_true_reg (&SET_DEST (i2set));
+             rtx i2src = SET_SRC (i2set);
+             if (GET_CODE (i2src) == FLOAT_EXTEND)
+               i2src = XEXP (i2src, 0);
              /* If the last two insns before insn that involve
                 stack regs are loads, where the latter (i1)
                 pushes onto the register stack and thus
@@ -937,9 +943,9 @@ emit_swap_insn (rtx_insn *insn, stack_pt
                 %st to %st(1), consider swapping them.  */
              if (REG_P (i2dest)
                  && REGNO (i2dest) == FIRST_STACK_REG
-                 && MEM_P (SET_SRC (i2set))
+                 && MEM_P (i2src)
                  /* Ensure i2 doesn't have other side-effects.  */
-                 && !side_effects_p (SET_SRC (i2set))
+                 && !side_effects_p (i2src)
                  /* And that the two instructions can actually be
                     swapped, i.e. there shouldn't be any stores
                     in between i2 and i1 that might alias with

?