rs6000.c (print_operand): Revise code that unsafely relied on signed overflow behavior.

2012-05-18  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	* config/rs6000/rs6000.c (print_operand): Revise code that unsafely
	relied on signed overflow behavior.

From-SVN: r187657

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b0d92ae..95bf7f9 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2012-05-18  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+       * config/rs6000/rs6000.c (print_operand): Revise code that unsafely
+       relied on signed overflow behavior.
+
 2012-05-18  Richard Guenther  <rguenther@suse.de>
 
        PR tree-optimization/53346

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index a03d24d..0896af3 100644 (file)
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -14679,7 +14679,6 @@ void
 print_operand (FILE *file, rtx x, int code)
 {
   int i;
-  HOST_WIDE_INT val;
   unsigned HOST_WIDE_INT uval;
 
   switch (code)
@@ -15120,34 +15119,17 @@ print_operand (FILE *file, rtx x, int code)
 
     case 'W':
       /* MB value for a PowerPC64 rldic operand.  */
-      val = (GET_CODE (x) == CONST_INT
-            ? INTVAL (x) : CONST_DOUBLE_HIGH (x));
-
-      if (val < 0)
-       i = -1;
-      else
-       for (i = 0; i < HOST_BITS_PER_WIDE_INT; i++)
-         if ((val <<= 1) < 0)
-           break;
+      i = clz_hwi (GET_CODE (x) == CONST_INT
+                  ? INTVAL (x) : CONST_DOUBLE_HIGH (x));
 
 #if HOST_BITS_PER_WIDE_INT == 32
-      if (GET_CODE (x) == CONST_INT && i >= 0)
+      if (GET_CODE (x) == CONST_INT && i > 0)
        i += 32;  /* zero-extend high-part was all 0's */
       else if (GET_CODE (x) == CONST_DOUBLE && i == 32)
-       {
-         val = CONST_DOUBLE_LOW (x);
-
-         gcc_assert (val);
-         if (val < 0)
-           --i;
-         else
-           for ( ; i < 64; i++)
-             if ((val <<= 1) < 0)
-               break;
-       }
+       i = clz_hwi (CONST_DOUBLE_LOW (x)) + 32;
 #endif
 
-      fprintf (file, "%d", i + 1);
+      fprintf (file, "%d", i);
       return;
 
     case 'x':