re PR rtl-optimization/17513 (ICE: verify_flow_info failed after gcse)

        PR tree-optimization/17513
	* cfgexpand.c (construct_init_block): Clear EDGE_EXECUTABLE
	for successors of the entry block.

	* gcc.dg/20040916-1.c: New test.

From-SVN: r87632

gcc/ChangeLog

+2004-09-17  Steven Bosscher  <stevenb@suse.de>
+
+        PR tree-optimization/17513
+	* cfgexpand.c (construct_init_block): Clear EDGE_EXECUTABLE
+	for successors of the entry block.
+
 2004-09-17  Uros Bizjak  <uros@kss-loka.si>
 
 	PR rtl-optimization/15187

gcc/cfgexpand.c

@@ -1082,11 +1082,21 @@ static basic_block
 construct_init_block (void)
 {
   basic_block init_block, first_block;
-  edge e;
+  edge e = NULL, e2;
+
+  for (e2 = ENTRY_BLOCK_PTR->succ; e2; e2 = e2->succ_next)
+    {
+      /* Clear EDGE_EXECUTABLE.  This flag is never used in the backend.
 
-  for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
-    if (e->dest == ENTRY_BLOCK_PTR->next_bb)
-      break;
+	 For all other blocks this edge flag is cleared while expanding
+	 a basic block in expand_gimple_basic_block, but there we never
+	 looked at the successors of the entry block.
+	 This caused PR17513.  */
+      e2->flags &= ~EDGE_EXECUTABLE;
+
+      if (e2->dest == ENTRY_BLOCK_PTR->next_bb)
+	e = e2;
+    }
 
   init_block = create_basic_block (NEXT_INSN (get_insns ()),
 				   get_last_insn (),

gcc/testsuite/ChangeLog

+2004-09-17  Steven Bosscher  <stevenb@suse.de>
+
+	PR tree-optimization/17513
+	* gcc.dg/20040916-1.c: New test.
+
 2004-09-16  Mark Mitchell  <mark@codesourcery.com>
 
 	PR c++/17501

gcc/testsuite/gcc.dg/20040916-1.c

+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+/* PR17513 - we hit a bug where EDGE_EXECUTABLE was not cleared on
+   successors of the entry block.  This lead to a flow verification
+   error much later in the compilation (after gcse).  */
+typedef unsigned char uint8; 
+typedef unsigned int uint32; 
+ 
+uint32 marker = 0; 
+uint8 *buff = 0; 
+uint32 bsize = 0; 
+ 
+extern int foo (void); 
+ 
+uint32 
+bar (void) 
+{ 
+  int len, d; 
+ 
+  for (;;) 
+    { 
+      if (foo () == 0) 
+        return (0); 
+ 
+      switch (marker) 
+        { 
+        case 0xfe: 
+          { 
+            len |= (*buff++); 
+            bsize -= 2; 
+ 
+            while (len > 0) 
+              { 
+                d = *buff++; 
+                len--; 
+              } 
+          } 
+          break; 
+        default: 
+          break; 
+        } 
+    } 
+} 
+