[cse][3/4] Don't overwrite original rtx when folding source of set

	PR target/65932
	PR target/67714
	* cse.c (cse_insn): Pass NULL to fold_rtx when initially
	folding the source of a SET.

From-SVN: r233133

gcc/ChangeLog

@@ -2,6 +2,13 @@
 
 	PR target/65932
 	PR target/67714
+	* cse.c (cse_insn): Pass NULL to fold_rtx when initially
+	folding the source of a SET.
+
+2016-02-04  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	PR target/65932
+	PR target/67714
 	* config/arm/arm.c (arm_new_rtx_costs, MULT case): Properly extract
 	the operands of the SIGN_EXTENDs from a SMUL[TB][TB] rtx.
 

gcc/cse.c

@@ -4636,7 +4636,7 @@ cse_insn (rtx_insn *insn)
 
       /* Simplify and foldable subexpressions in SRC.  Then get the fully-
 	 simplified result, which may not necessarily be valid.  */
-      src_folded = fold_rtx (src, insn);
+      src_folded = fold_rtx (src, NULL);
 
 #if 0
       /* ??? This caused bad code to be generated for the m68k port with -O2.