re PR tree-optimization/34099 (optimizer problem)

2007-11-19  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/34099
	* tree-ssa-ccp.c (likely_value): Exclude all but PLUS_EXPR,
	MINUS_EXPR and POINTER_PLUS_EXPR from handling as UNDEFINED
	if only one operand is undefined.

	* gcc.c-torture/execute/pr34099-2.c: New testcase.

From-SVN: r130289

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4fafa8dc9363df4e11312ebfcb7ff322202d168e..97f6a0806ea68c5715c0f614a66117c51fe25f75 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2007-11-19  Richard Guenther  <rguenther@suse.de>
+
+       PR tree-optimization/34099
+       * tree-ssa-ccp.c (likely_value): Exclude all but PLUS_EXPR,
+       MINUS_EXPR and POINTER_PLUS_EXPR from handling as UNDEFINED
+       if only one operand is undefined.
+
 2007-11-19  Eric Botcazou  <ebotcazou@libertysurf.fr>
 
        PR tree-optimization/34036

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr34099-2.c b/gcc/testsuite/gcc.c-torture/execute/pr34099-2.c
new file mode 100644 (file)
index 0000000..d335673
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr34099-2.c
@@ -0,0 +1,47 @@
+int test1 (int b, int c)
+{
+  char x;
+  if (b)
+    return x / c;
+  else
+    return 1;
+}
+int test2 (int b, int c)
+{
+  int x;
+  if (b)
+    return x * c;
+  else
+    return 1;
+}
+int test3 (int b, int c)
+{
+  int x;
+  if (b)
+    return x % c;
+  else
+    return 1;
+}
+int test4 (int b, int c)
+{
+  char x;
+  if (b)
+    return x == c;
+  else
+    return 1;
+}
+
+extern void abort (void);
+int main()
+{
+  if (test1(1, 1000) != 0)
+    abort ();
+  if (test2(1, 0) != 0)
+    abort ();
+  if (test3(1, 1) != 0)
+    abort ();
+  if (test4(1, 1000) != 0)
+    abort ();
+  return 0;
+}
+

diff --git a/gcc/tree-ssa-ccp.c b/gcc/tree-ssa-ccp.c
index fc40449be8db8584d0ee0ca15963e0e8275ffd29..19d82563a81379748dd894869c8aef020a6b370f 100644 (file)
--- a/gcc/tree-ssa-ccp.c
+++ b/gcc/tree-ssa-ccp.c
@@ -582,32 +582,13 @@ likely_value (tree stmt)
        /* Unary operators are handled with all_undefined_operands.  */
        case PLUS_EXPR:
        case MINUS_EXPR:
-       case MULT_EXPR:
        case POINTER_PLUS_EXPR:
-       case TRUNC_DIV_EXPR:
-       case CEIL_DIV_EXPR:
-       case FLOOR_DIV_EXPR:
-       case ROUND_DIV_EXPR:
-       case TRUNC_MOD_EXPR:
-       case CEIL_MOD_EXPR:
-       case FLOOR_MOD_EXPR:
-       case ROUND_MOD_EXPR:
-       case RDIV_EXPR:
-       case EXACT_DIV_EXPR:
-       case LSHIFT_EXPR:
-       case RSHIFT_EXPR:
-       case LROTATE_EXPR:
-       case RROTATE_EXPR:
-       case EQ_EXPR:
-       case NE_EXPR:
-       case LT_EXPR:
-       case GT_EXPR:
          /* Not MIN_EXPR, MAX_EXPR.  One VARYING operand may be selected.
             Not bitwise operators, one VARYING operand may specify the
             result completely.  Not logical operators for the same reason.
-            Not LE/GE comparisons or unordered comparisons.  Not
-            COMPLEX_EXPR as one VARYING operand makes the result partly
-            not UNDEFINED.  */
+            Not COMPLEX_EXPR as one VARYING operand makes the result partly
+            not UNDEFINED.  Not *DIV_EXPR, comparisons and shifts because
+            the undefined operand may be promoted.  */
          return UNDEFINED;
 
        default: