expmed: Fix possible use of NULL_RTX return value from emit_store_flag

MSP430 does not support have any store-flag instructions, so
emit_store_flag can return NULL_RTX.  Catch the NULL_RTX in
expmed.c:expand_sdiv_pow2.

gcc/ChangeLog:

	* expmed.c (expand_sdiv_pow2): Check return value from emit_store_flag
	is not NULL_RTX before use.

diff --git a/gcc/expmed.c b/gcc/expmed.c
index e7c03fb..3d2d234 100644 (file)
--- a/gcc/expmed.c
+++ b/gcc/expmed.c
@@ -4086,9 +4086,12 @@ expand_sdiv_pow2 (scalar_int_mode mode, rtx op0, HOST_WIDE_INT d)
     {
       temp = gen_reg_rtx (mode);
       temp = emit_store_flag (temp, LT, op0, const0_rtx, mode, 0, 1);
-      temp = expand_binop (mode, add_optab, temp, op0, NULL_RTX,
-                          0, OPTAB_LIB_WIDEN);
-      return expand_shift (RSHIFT_EXPR, mode, temp, logd, NULL_RTX, 0);
+      if (temp != NULL_RTX)
+       {
+         temp = expand_binop (mode, add_optab, temp, op0, NULL_RTX,
+                              0, OPTAB_LIB_WIDEN);
+         return expand_shift (RSHIFT_EXPR, mode, temp, logd, NULL_RTX, 0);
+       }
     }
 
   if (HAVE_conditional_move
@@ -4122,17 +4125,21 @@ expand_sdiv_pow2 (scalar_int_mode mode, rtx op0, HOST_WIDE_INT d)
 
       temp = gen_reg_rtx (mode);
       temp = emit_store_flag (temp, LT, op0, const0_rtx, mode, 0, -1);
-      if (GET_MODE_BITSIZE (mode) >= BITS_PER_WORD
-         || shift_cost (optimize_insn_for_speed_p (), mode, ushift)
-            > COSTS_N_INSNS (1))
-       temp = expand_binop (mode, and_optab, temp, gen_int_mode (d - 1, mode),
-                            NULL_RTX, 0, OPTAB_LIB_WIDEN);
-      else
-       temp = expand_shift (RSHIFT_EXPR, mode, temp,
-                            ushift, NULL_RTX, 1);
-      temp = expand_binop (mode, add_optab, temp, op0, NULL_RTX,
-                          0, OPTAB_LIB_WIDEN);
-      return expand_shift (RSHIFT_EXPR, mode, temp, logd, NULL_RTX, 0);
+      if (temp != NULL_RTX)
+       {
+         if (GET_MODE_BITSIZE (mode) >= BITS_PER_WORD
+             || shift_cost (optimize_insn_for_speed_p (), mode, ushift)
+             > COSTS_N_INSNS (1))
+           temp = expand_binop (mode, and_optab, temp,
+                                gen_int_mode (d - 1, mode),
+                                NULL_RTX, 0, OPTAB_LIB_WIDEN);
+         else
+           temp = expand_shift (RSHIFT_EXPR, mode, temp,
+                                ushift, NULL_RTX, 1);
+         temp = expand_binop (mode, add_optab, temp, op0, NULL_RTX,
+                              0, OPTAB_LIB_WIDEN);
+         return expand_shift (RSHIFT_EXPR, mode, temp, logd, NULL_RTX, 0);
+       }
     }
 
   label = gen_label_rtx ();