[backport gcc-4.8/trunk r193187 to fix final_scan_insn on m68k/cc0 targets <mikpe@it.uu.se>]

From: Andreas Schwab <schwab at linux-m68k dot org>
Subject: [PATCH] Fix final_scan_insn to handle all comparisons in non-jump and cmove insn
Date: Sat, 03 Nov 2012 14:16:25 +0100
List-Archive: <http://gcc.gnu.org/ml/gcc-patches/>

final_scan_insn didn't handle the IEEE-aware compares in a
non-jump/cmove insn, causing wrong code if it was generated with swapped
operands (CC_REVERSED set).  Tested on m68k-linux.

Andreas.

	* final.c (final_scan_insn) [HAVE_cc0]: Handle all comparison
	codes in non-jump and cmove insn.

testsuite/
	* gcc.dg/torture/fp-compare.c: New testcase.

--- gcc-4.7.2/gcc/final.c.~1~	2011-12-13 14:41:12.000000000 +0100
+++ gcc-4.7.2/gcc/final.c	2012-11-03 16:55:08.000000000 +0100
@@ -2566,36 +2566,19 @@ final_scan_insn (rtx insn, FILE *file, i
 		else_rtx = const0_rtx;
 	      }
 
-	    switch (GET_CODE (cond_rtx))
+	    if (COMPARISON_P (cond_rtx)
+		&& XEXP (cond_rtx, 0) == cc0_rtx)
 	      {
-	      case GTU:
-	      case GT:
-	      case LTU:
-	      case LT:
-	      case GEU:
-	      case GE:
-	      case LEU:
-	      case LE:
-	      case EQ:
-	      case NE:
-		{
-		  int result;
-		  if (XEXP (cond_rtx, 0) != cc0_rtx)
-		    break;
-		  result = alter_cond (cond_rtx);
-		  if (result == 1)
-		    validate_change (insn, &SET_SRC (set), then_rtx, 0);
-		  else if (result == -1)
-		    validate_change (insn, &SET_SRC (set), else_rtx, 0);
-		  else if (result == 2)
-		    INSN_CODE (insn) = -1;
-		  if (SET_DEST (set) == SET_SRC (set))
-		    delete_insn (insn);
-		}
-		break;
-
-	      default:
-		break;
+		int result;
+		result = alter_cond (cond_rtx);
+		if (result == 1)
+		  validate_change (insn, &SET_SRC (set), then_rtx, 0);
+		else if (result == -1)
+		  validate_change (insn, &SET_SRC (set), else_rtx, 0);
+		else if (result == 2)
+		  INSN_CODE (insn) = -1;
+		if (SET_DEST (set) == SET_SRC (set))
+		  delete_insn (insn);
 	      }
 	  }
 
--- gcc-4.7.2/gcc/testsuite/gcc.dg/torture/fp-compare.c.~1~	1970-01-01 01:00:00.000000000 +0100
+++ gcc-4.7.2/gcc/testsuite/gcc.dg/torture/fp-compare.c	2012-11-03 16:55:08.000000000 +0100
@@ -0,0 +1,23 @@
+/* { dg-do run } */
+/* Check that find_scan_insn properly handles swapped FP comparisons.  */
+static double x;
+static int exit_code;
+
+void __attribute__ ((noinline))
+check_int (int a, int b)
+{
+  exit_code += (a != b);
+}
+
+int
+main (void)
+{
+  x = 0.0;
+  asm ("" : "+m" (x));
+  check_int (__builtin_isgreater (x, 1.0), 0);
+  check_int (__builtin_isgreaterequal (x, 1.0), 0);
+  check_int (__builtin_isless (x, 1.0), 1);
+  check_int (__builtin_islessequal (x, 1.0), 1);
+  check_int (__builtin_islessgreater (x, 1.0), 1);
+  return exit_code;
+}