From: Jeff Law <law@redhat.com>
Date: Wed, 19 May 2004 18:31:35 +0000 (-0600)
Subject: tree-ssa-phiopt.c (value_replacement): Handle the case where the desired edge out... 
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=84c672b950e3427d9abb5b74d635e586bda74c4e;p=gcc.git

tree-ssa-phiopt.c (value_replacement): Handle the case where the desired edge out of COND_BLOCK reaches OTHER_BLOCK...

	* tree-ssa-phiopt.c (value_replacement): Handle the case where
	the desired edge out of COND_BLOCK reaches OTHER_BLOCK rather than
	BB directly.

From-SVN: r82031
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 673dae6791a..2bdfb82e847 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2004-05-19  Jeff Law <law@redhat.com>
+
+	* tree-ssa-phiopt.c (value_replacement): Handle the case where
+	the desired edge out of COND_BLOCK reaches OTHER_BLOCK rather than
+	BB directly.
+
 2004-05-19  Zdenek Dvorak  <rakdver@atrey.karlin.mff.cuni.cz>
 
 	PR c++/15463
diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index 7648bc090d6..fa342700d65 100644
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -464,7 +464,20 @@ value_replacement (basic_block bb, tree phi, tree arg0, tree arg1)
       edge e;
       tree arg;
 
+      /* For NE_EXPR, we want to build an assignment result = arg where
+	 arg is the PHI argument associated with the true edge.  For
+	 EQ_EXPR we want the PHI argument associated with the false edge.  */
       e = (TREE_CODE (cond) == NE_EXPR ? true_edge : false_edge);
+
+      /* Unfortunately, E may not reach BB (it may instead have gone to
+	 OTHER_BLOCK).  If that is the case, then we want the single outgoing
+	 edge from OTHER_BLOCK which reaches BB and represents the desired
+	 path from COND_BLOCK.  */
+      if (e->dest == other_block)
+	e = e->dest->succ;
+
+      /* Now we know the incoming edge to BB that has the argument for the
+	 RHS of our new assignment statement.  */
       if (PHI_ARG_EDGE (phi, 0) == e)
 	arg = arg0;
       else