[committed] i386: Simplify PARALLEL RTX scan in ix86_find_all_reg_use

[Uros Bizjak]

UNSPEC and UNSPEC_VOLATILE never store. Remove unnecessary checks and
simplify RTX scan in ix86_find_all_reg_use to scan only for SET RTX
in the PARALLEL.

gcc/ChangeLog:

    * config/i386/i386.cc (ix86_find_all_reg_use):
    Scan only for SET RTX in PARALLEL.

Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.

Uros.

diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index fafd4a511a3..560e6525b56 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -8538,31 +8538,9 @@ ix86_find_all_reg_use (HARD_REG_SET &stack_slot_access,
       for (int i = 0; i < XVECLEN (pat, 0); i++)
        {
          rtx exp = XVECEXP (pat, 0, i);
-         switch (GET_CODE (exp))
-           {
-           case ASM_OPERANDS:
-           case CLOBBER:
-           case PREFETCH:
-           case USE:
-             break;
-           case UNSPEC:
-           case UNSPEC_VOLATILE:
-             for (int j = XVECLEN (exp, 0) - 1; j >= 0; j--)
-               {
-                 rtx x = XVECEXP (exp, 0, j);
-                 if (GET_CODE (x) == SET)
-                   ix86_find_all_reg_use_1 (x, stack_slot_access,
-                                            worklist);
-               }
-             break;
-           case SET:
-             ix86_find_all_reg_use_1 (exp, stack_slot_access,
-                                      worklist);
-             break;
-           default:
-             gcc_unreachable ();
-             break;
-           }
+
+         if (GET_CODE (exp) == SET)
+           ix86_find_all_reg_use_1 (exp, stack_slot_access, worklist);
        }
     }
 }