[backport from gcc-4.7/trunk <mikpe@it.uu.se>]

gcc/

2011-04-08  Michael Matz  <matz@suse.de>

	PR middle-end/48389
	* jump.c (rebuild_jump_labels_1, rebuild_jump_labels_chain): New
	functions.
	(rebuild_jump_labels): Call rebuild_jump_labels_1.
	* rtl.h (rebuild_jump_labels_chain): Declare.
	* cfgexpand.c (gimple_expand_cfg): Initialize JUMP_LABEL also on
	insns inserted on edges.

gcc/testsuite/

2011-04-08  Michael Matz  <matz@suse.de>

	PR middle-end/48389
	* gcc.target/i386/pr48389.c: New test.

--- gcc-4.6.0/gcc/cfgexpand.c.~1~	2011-03-03 17:06:33.000000000 +0100
+++ gcc-4.6.0/gcc/cfgexpand.c	2011-05-15 15:26:42.000000000 +0200
@@ -4127,6 +4127,8 @@ gimple_expand_cfg (void)
   /* Zap the tree EH table.  */
   set_eh_throw_stmt_table (cfun, NULL);
 
+  /* We need JUMP_LABEL be set in order to redirect jumps, and hence
+     split edges which edge insertions might do.  */
   rebuild_jump_labels (get_insns ());
 
   FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
@@ -4137,6 +4139,7 @@ gimple_expand_cfg (void)
 	{
 	  if (e->insns.r)
 	    {
+	      rebuild_jump_labels_chain (e->insns.r);
 	      /* Avoid putting insns before parm_birth_insn.  */
 	      if (e->src == ENTRY_BLOCK_PTR
 		  && single_succ_p (ENTRY_BLOCK_PTR)
--- gcc-4.6.0/gcc/jump.c.~1~	2010-12-13 04:08:24.000000000 +0100
+++ gcc-4.6.0/gcc/jump.c	2011-05-15 15:26:42.000000000 +0200
@@ -72,12 +72,9 @@ static void redirect_exp_1 (rtx *, rtx, 
 static int invert_exp_1 (rtx, rtx);
 static int returnjump_p_1 (rtx *, void *);
 
-/* This function rebuilds the JUMP_LABEL field and REG_LABEL_TARGET
-   notes in jumping insns and REG_LABEL_OPERAND notes in non-jumping
-   instructions and jumping insns that have labels as operands
-   (e.g. cbranchsi4).  */
-void
-rebuild_jump_labels (rtx f)
+/* Worker for rebuild_jump_labels and rebuild_jump_labels_chain.  */
+static void
+rebuild_jump_labels_1 (rtx f, bool count_forced)
 {
   rtx insn;
 
@@ -89,11 +86,31 @@ rebuild_jump_labels (rtx f)
      closely enough to delete them here, so make sure their reference
      count doesn't drop to zero.  */
 
-  for (insn = forced_labels; insn; insn = XEXP (insn, 1))
-    if (LABEL_P (XEXP (insn, 0)))
-      LABEL_NUSES (XEXP (insn, 0))++;
+  if (count_forced)
+    for (insn = forced_labels; insn; insn = XEXP (insn, 1))
+      if (LABEL_P (XEXP (insn, 0)))
+	LABEL_NUSES (XEXP (insn, 0))++;
   timevar_pop (TV_REBUILD_JUMP);
 }
+
+/* This function rebuilds the JUMP_LABEL field and REG_LABEL_TARGET
+   notes in jumping insns and REG_LABEL_OPERAND notes in non-jumping
+   instructions and jumping insns that have labels as operands
+   (e.g. cbranchsi4).  */
+void
+rebuild_jump_labels (rtx f)
+{
+  rebuild_jump_labels_1 (f, true);
+}
+
+/* This function is like rebuild_jump_labels, but doesn't run over
+   forced_labels.  It can be used on insn chains that aren't the 
+   main function chain.  */
+void
+rebuild_jump_labels_chain (rtx chain)
+{
+  rebuild_jump_labels_1 (chain, false);
+}
 
 /* Some old code expects exactly one BARRIER as the NEXT_INSN of a
    non-fallthru insn.  This is not generally true, as multiple barriers
--- gcc-4.6.0/gcc/rtl.h.~1~	2011-03-09 21:49:00.000000000 +0100
+++ gcc-4.6.0/gcc/rtl.h	2011-05-15 15:26:42.000000000 +0200
@@ -2311,6 +2311,7 @@ extern int redirect_jump_1 (rtx, rtx);
 extern void redirect_jump_2 (rtx, rtx, rtx, int, int);
 extern int redirect_jump (rtx, rtx, int);
 extern void rebuild_jump_labels (rtx);
+extern void rebuild_jump_labels_chain (rtx);
 extern rtx reversed_comparison (const_rtx, enum machine_mode);
 extern enum rtx_code reversed_comparison_code (const_rtx, const_rtx);
 extern enum rtx_code reversed_comparison_code_parts (enum rtx_code, const_rtx,
--- gcc-4.6.0/gcc/testsuite/gcc.target/i386/pr48389.c.~1~	1970-01-01 01:00:00.000000000 +0100
+++ gcc-4.6.0/gcc/testsuite/gcc.target/i386/pr48389.c	2011-05-15 15:26:42.000000000 +0200
@@ -0,0 +1,13 @@
+/* PR middle-end/48389 */
+/* { dg-do compile } */
+/* { dg-options "-O -mtune=pentiumpro -Wno-abi" } */
+/* { dg-require-effective-target ilp32 } */
+typedef float V2SF __attribute__ ((vector_size (128)));
+V2SF foo (int x, V2SF a)
+{
+  V2SF b = {};
+  if (x & 42)
+    b = a;
+  a += b;
+  return a;
+}