cse.c (find_comparison_args): Remove previous change.

	* cse.c (find_comparison_args): Remove previous change.
	* ifcvt.c (noce_process_if_block): When moving an insn, remove any
	REG_EQUAL notes.

From-SVN: r40715

gcc/ChangeLog

 Wed Mar 21 14:27:11 2001  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
 
+	* cse.c (find_comparison_args): Remove previous change.
+	* ifcvt.c (noce_process_if_block): When moving an insn, remove any
+	REG_EQUAL notes.
+
 	* config/i386/i386.md (conditional_trap): Remove warning.
 
 	* recog.c (push_operand): Fix error in last change that caused

gcc/cse.c

@@ -3086,25 +3086,17 @@ find_best_addr (insn, loc, mode)
 #endif
 }
 
-/* This routine accepts a comparison as input and attempts to return a
-   comparision that is cheaper to compute.
+/* Given an operation (CODE, *PARG1, *PARG2), where code is a comparison
+   operation (EQ, NE, GT, etc.), follow it back through the hash table and
+   what values are being compared.
 
-   On input, *PARG1 and *PARG2 should be set to the first and second
-   arguments to the comparison, respectively.  CODE is the comparision
-   code.  For example, if the comparison is:
+   *PARG1 and *PARG2 are updated to contain the rtx representing the values
+   actually being compared.  For example, if *PARG1 was (cc0) and *PARG2
+   was (const_int 0), *PARG1 and *PARG2 will be set to the objects that were
+   compared to produce cc0.
 
-     (ne:SI (reg:CC 24 cc)
-            (const_int 0 [0x0])))
-
-   The CODE should be NE, *PARG1 should be `(reg:CC 24 cc)' and 
-   *PARG2 should be `(const_int 0)'.
-
-   Upon return, *PARG1 and and *PARG2 may have new values, indicating
-   arguments to a cheaper comparison.  *PMODE1 and *PMODE2 will be the
-   modes that should be used for those arguments.  The return value
-   itself will be the comparison code that should be used to compare
-   *PARG1 and *PARG2 in order to obtain a value equivalent to that
-   given by the original comparison.  */
+   The return value is the comparison operator and is either the code of
+   A or the code corresponding to the inverse of the comparison.  */
 
 static enum rtx_code
 find_comparison_args (code, parg1, parg2, pmode1, pmode2)
@@ -3195,38 +3187,30 @@ find_comparison_args (code, parg1, parg2, pmode1, pmode2)
 	  if (! exp_equiv_p (p->exp, p->exp, 1, 0))
 	    continue;
 
-	  /* `(COMPARE A B) != 0)' is equivalent to `(COMPARE A B)'.
-	     If CODE is EQ, rather than NE, then we are out of luck;
-	     there is no way to reverse the sense of a COMPARE.  */
-	  if (code == NE && GET_CODE (p->exp) == COMPARE)
-	    {
-	      x = p->exp;
-	      break;
-	    }
-	  /* Another possibility is that this machine has a compare
-	     insn that includes the comparison code.  In that case,
-	     ARG1 would be equivalent to a comparison operation that
-	     would set ARG1 to either STORE_FLAG_VALUE or zero.  If
-	     this is an NE operation, ORIG_CODE is the actual
-	     comparison being done; if it is an EQ, we must reverse
-	     ORIG_CODE.  On machine with a negative value for
-	     STORE_FLAG_VALUE, also look at LT and GE operations.  */
-	  else if ((code == NE
-		    || (code == LT
-			&& GET_MODE_CLASS (inner_mode) == MODE_INT
-			&& (GET_MODE_BITSIZE (inner_mode)
-			    <= HOST_BITS_PER_WIDE_INT)
-			&& (STORE_FLAG_VALUE
-			    & ((HOST_WIDE_INT) 1
-			       << (GET_MODE_BITSIZE (inner_mode) - 1))))
+	  if (GET_CODE (p->exp) == COMPARE
+	      /* Another possibility is that this machine has a compare insn
+		 that includes the comparison code.  In that case, ARG1 would
+		 be equivalent to a comparison operation that would set ARG1 to
+		 either STORE_FLAG_VALUE or zero.  If this is an NE operation,
+		 ORIG_CODE is the actual comparison being done; if it is an EQ,
+		 we must reverse ORIG_CODE.  On machine with a negative value
+		 for STORE_FLAG_VALUE, also look at LT and GE operations.  */
+	      || ((code == NE
+		   || (code == LT
+		       && GET_MODE_CLASS (inner_mode) == MODE_INT
+		       && (GET_MODE_BITSIZE (inner_mode)
+			   <= HOST_BITS_PER_WIDE_INT)
+		       && (STORE_FLAG_VALUE
+			   & ((HOST_WIDE_INT) 1
+			      << (GET_MODE_BITSIZE (inner_mode) - 1))))
 #ifdef FLOAT_STORE_FLAG_VALUE
-		    || (code == LT
-			&& GET_MODE_CLASS (inner_mode) == MODE_FLOAT
-			&& (REAL_VALUE_NEGATIVE
-			    (FLOAT_STORE_FLAG_VALUE (GET_MODE (arg1)))))
+		   || (code == LT
+		       && GET_MODE_CLASS (inner_mode) == MODE_FLOAT
+		       && (REAL_VALUE_NEGATIVE
+			   (FLOAT_STORE_FLAG_VALUE (GET_MODE (arg1)))))
 #endif
-		    )
-		   && GET_RTX_CLASS (GET_CODE (p->exp)) == '<')
+		   )
+		  && GET_RTX_CLASS (GET_CODE (p->exp)) == '<'))
 	    {
 	      x = p->exp;
 	      break;

gcc/ifcvt.c

@@ -1563,9 +1563,17 @@ noce_process_if_block (test_bb, then_bb, else_bb, join_bb)
 	 that case don't do anything and let the code below delete INSN_A.  */
       if (insn_b && else_bb)
 	{
+	  rtx note;
+
 	  if (else_bb && insn_b == else_bb->end)
 	    else_bb->end = PREV_INSN (insn_b);
 	  reorder_insns (insn_b, insn_b, PREV_INSN (if_info.cond_earliest));
+
+	  /* If there was a REG_EQUAL note, delete it since it may have been
+	     true due to this insn being after a jump.  */
+	  if ((note = find_reg_note (insn_b, REG_EQUAL, NULL_RTX)) != 0)
+	    remove_note (insn_b, note);
+
 	  insn_b = NULL_RTX;
 	}
       /* If we have "x = b; if (...) x = a;", and x has side-effects, then