From: Jim Wilson <wilson@gcc.gnu.org>
Date: Tue, 21 Dec 1993 18:25:26 +0000 (-0800)
Subject: (replace_regs, case REG): Return copies of SUBREGs, to
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=3eb8f14cbc240ac542ac954dccf0fe8569cc1c30;p=gcc.git

(replace_regs, case REG): Return copies of SUBREGs, to
avoid invalid sharing.

From-SVN: r6253
---

diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c
index 48aa6f9d688..486ef5f8d22 100644
--- a/gcc/rtlanal.c
+++ b/gcc/rtlanal.c
@@ -1662,7 +1662,14 @@ replace_regs (x, reg_map, nregs, replace_dest)
     case REG:
       /* Verify that the register has an entry before trying to access it.  */
       if (REGNO (x) < nregs && reg_map[REGNO (x)] != 0)
-	return reg_map[REGNO (x)];
+	{
+	  /* SUBREGs can't be shared.  Always return a copy to ensure that if
+	     this replacement occurs more than once then each instance will
+	     get distinct rtx.  */
+	  if (GET_CODE (reg_map[REGNO (x)]) == SUBREG)
+	    return copy_rtx (reg_map[REGNO (x)]);
+	  return reg_map[REGNO (x)];
+	}
       return x;
 
     case SUBREG: