reload.h (elimination_target_reg_p): Declare.

gcc/
	* reload.h (elimination_target_reg_p): Declare.
	* reload.c (find_reloads): Don't apply the reg_rtx move
	optimization if the SET_DEST satisfies elimination_target_reg_p.
	* reload1.c (elimination_target_reg_p): New function.
	(gen_reload): In the move/add2 fallback, make sure that op0
	does not overlap the destination register.

From-SVN: r124215

1 files changed, 15 insertions, 0 deletions

diff --git a/gcc/reload1.c b/gcc/reload1.c
index 9ee046a..4d2dea5 100644
--- a/gcc/reload1.c
+++ b/gcc/reload1.c
@@ -3607,6 +3607,20 @@ update_eliminables (HARD_REG_SET *pset)
     SET_HARD_REG_BIT (*pset, HARD_FRAME_POINTER_REGNUM);
 }
 
+/* Return true if X is used as the target register of an elimination.  */
+
+bool
+elimination_target_reg_p (rtx x)
+{
+  struct elim_table *ep;
+
+  for (ep = reg_eliminate; ep < &reg_eliminate[NUM_ELIMINABLE_REGS]; ep++)
+    if (ep->to_rtx == x && ep->can_eliminate)
+      return true;
+
+  return false;
+}
+
 /* Initialize the table of registers to eliminate.  */
 
 static void
@@ -7873,6 +7887,7 @@ gen_reload (rtx out, rtx in, int opnum, enum reload_type type)
       /* If that failed, copy the address register to the reload register.
 	 Then add the constant to the reload register.  */
 
+      gcc_assert (!reg_overlap_mentioned_p (out, op0));
       gen_reload (out, op1, opnum, type);
       insn = emit_insn (gen_add2_insn (out, op0));
       set_unique_reg_note (insn, REG_EQUIV, in);