From: Uros Bizjak <ubizjak@gmail.com>
Date: Wed, 31 Jan 2018 21:37:54 +0000 (+0100)
Subject: re PR rtl-optimization/84123 (internal compiler error: in gen_rtx_SUBREG, at emit... 
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=c677f80adb4a075f3549a2aedde4ae9fdcb847c0;p=gcc.git

re PR rtl-optimization/84123 (internal compiler error: in gen_rtx_SUBREG, at emit-rtl.c:908, alpha linux.)

	PR rtl-optimization/84123
	* combine.c (change_zero_ext): Check if hard register satisfies
	can_change_dest_mode before calling gen_lowpart_SUBREG.

From-SVN: r257270
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6c03ceea32b..88df7ab9c19 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2018-01-31  Uros Bizjak  <ubizjak@gmail.com>
+
+	PR rtl-optimization/84123
+	* combine.c (change_zero_ext): Check if hard register satisfies
+	can_change_dest_mode before calling gen_lowpart_SUBREG.
+
 2018-01-31  Vladimir Makarov  <vmakarov@redhat.com>
 
 	PR target/82444
diff --git a/gcc/combine.c b/gcc/combine.c
index b14b248800e..970dd26778e 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -11480,8 +11480,15 @@ change_zero_ext (rtx pat)
 				  gen_int_shift_amount (inner_mode, start));
 	  else
 	    x = XEXP (x, 0);
+
 	  if (mode != inner_mode)
-	    x = gen_lowpart_SUBREG (mode, x);
+	    {
+	      if (HARD_REGISTER_P (x)
+		  && !can_change_dest_mode (x, 0, mode))
+		continue;
+
+	      x = gen_lowpart_SUBREG (mode, x);
+	    }
 	}
       else if (GET_CODE (x) == ZERO_EXTEND
 	       && GET_CODE (XEXP (x, 0)) == SUBREG
@@ -11493,7 +11500,13 @@ change_zero_ext (rtx pat)
 	  size = GET_MODE_PRECISION (inner_mode);
 	  x = SUBREG_REG (XEXP (x, 0));
 	  if (GET_MODE (x) != mode)
-	    x = gen_lowpart_SUBREG (mode, x);
+	    {
+	      if (HARD_REGISTER_P (x)
+		  && !can_change_dest_mode (x, 0, mode))
+		continue;
+
+	      x = gen_lowpart_SUBREG (mode, x);
+	    }
 	}
       else if (GET_CODE (x) == ZERO_EXTEND
 	       && REG_P (XEXP (x, 0))