[rtl] Harden 'set_noop_p' for non-constant selectors [PR94279]

... given that the GCN target did away with the constant 'vec_select'
restriction.

	gcc/
	PR target/94279
	* rtlanal.c (set_noop_p): Handle non-constant selectors.

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2ba39f67200f28d29906c31d292d291b6056fc50..ef851ef84626c45d5ce60e46a1a5a3d527489f50 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,8 @@
 2020-04-29  Thomas Schwinge  <thomas@codesourcery.com>
 
+       PR target/94279
+       * rtlanal.c (set_noop_p): Handle non-constant selectors.
+
        PR target/94282
        * common/config/gcn/gcn-common.c (gcn_except_unwind_info): New
        function.

diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c
index c7ab86e228b1fe4c3645d7746b5c1ae046b0f821..0ebde7622db6bcc70af7a4401ad27d08fbc14c9d 100644 (file)
--- a/gcc/rtlanal.c
+++ b/gcc/rtlanal.c
@@ -1631,12 +1631,18 @@ set_noop_p (const_rtx set)
       int i;
       rtx par = XEXP (src, 1);
       rtx src0 = XEXP (src, 0);
-      poly_int64 c0 = rtx_to_poly_int64 (XVECEXP (par, 0, 0));
+      poly_int64 c0;
+      if (!poly_int_rtx_p (XVECEXP (par, 0, 0), &c0))
+       return 0;
       poly_int64 offset = GET_MODE_UNIT_SIZE (GET_MODE (src0)) * c0;
 
       for (i = 1; i < XVECLEN (par, 0); i++)
-       if (maybe_ne (rtx_to_poly_int64 (XVECEXP (par, 0, i)), c0 + i))
-         return 0;
+       {
+         poly_int64 c0i;
+         if (!poly_int_rtx_p (XVECEXP (par, 0, i), &c0i)
+             || maybe_ne (c0i, c0 + i))
+           return 0;
+       }
       return
        REG_CAN_CHANGE_MODE_P (REGNO (dst), GET_MODE (src0), GET_MODE (dst))
        && simplify_subreg_regno (REGNO (src0), GET_MODE (src0),