From: Alexandre Oliva <aoliva@redhat.com>
Date: Thu, 14 Feb 2002 19:30:42 +0000 (+0000)
Subject: combine.c (known_cond): After replacing the REG of a SUBREG, try to simplify it.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=9a360704f9edf14fd0dd3a04dcf16923164c09b2;p=gcc.git

combine.c (known_cond): After replacing the REG of a SUBREG, try to simplify it.

* combine.c (known_cond): After replacing the REG of a SUBREG, try
to simplify it.

From-SVN: r49775
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e23395e7524..82649c55d70 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,8 @@
 2002-02-14  Alexandre Oliva  <aoliva@redhat.com>
 
+	* combine.c (known_cond): After replacing the REG of a SUBREG, try
+	to simplify it.
+
 	* function.c (assign_parms): Demote promoted argument passed by
 	transparent reference.
 
diff --git a/gcc/combine.c b/gcc/combine.c
index ba0bf35d21e..5abda2e56fe 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -7430,6 +7430,25 @@ known_cond (x, cond, reg, val)
 	    }
 	}
     }
+  else if (code == SUBREG)
+    {
+      enum machine_mode inner_mode = GET_MODE (SUBREG_REG (x));
+      rtx new, r = known_cond (SUBREG_REG (x), cond, reg, val);
+
+      if (SUBREG_REG (x) != r)
+	{
+	  /* We must simplify subreg here, before we lose track of the
+	     original inner_mode.  */
+	  new = simplify_subreg (GET_MODE (x), r,
+				 inner_mode, SUBREG_BYTE (x));
+	  if (new)
+	    return new;
+	  else
+	    SUBST (SUBREG_REG (x), r);
+	}
+
+      return x;
+    }
 
   fmt = GET_RTX_FORMAT (code);
   for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)