re PR rtl-optimization/84123 (internal compiler error: in gen_rtx_SUBREG, at emit...

	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 6c03ceea32b6d6d7f6389a987c73adbb72ae9a0d..88df7ab9c1992ae9dee2748ed8911bfb895b7ecc 100644 (file)
--- 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 b14b248800e25e6f418d885f873a5e05b54b3502..970dd26778e80c2dbb51969ddb7ecb4618ffad6b 100644 (file)
--- 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))