[combine] Don't create LSHIFTRT of zero bits in change_zero_ext

* combine.c (change_zero_ext): Do not create a shift of zero length. From-SVN: r231613

[combine] Don't create LSHIFTRT of zero bits in change_zero_ext
* combine.c (change_zero_ext): Do not create a shift of zero length. From-SVN: r231613
adb48173 · Kyrylo Tkachov · Kyrylo Tkachov · f5a8c224 · adb48173 · adb48173
Commit adb48173 authored Dec 14, 2015 by Kyrylo Tkachov Committed by Kyrylo Tkachov Dec 14, 2015
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gcc/ChangeLog
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gcc/combine.c
+2 -1

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--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
+2015-12-14  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	* combine.c (change_zero_ext): Do not create a shift of zero length.
+
 2015-12-14  Claudiu Zissulescu  <claziss@synopsys.com>

 	* config/arc/arc.c (TARGET_NO_SPECULATION_IN_DELAY_SLOTS_P):
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -11045,7 +11045,8 @@ change_zero_ext (rtx *src)
 	  if (BITS_BIG_ENDIAN)
 	    start = GET_MODE_PRECISION (mode) - size - start;

-	  x = gen_rtx_LSHIFTRT (mode, XEXP (x, 0), GEN_INT (start));
+	  x = simplify_gen_binary (LSHIFTRT, mode,
+				   XEXP (x, 0), GEN_INT (start));
 	}
      else if (GET_CODE (x) == ZERO_EXTEND
 	       && GET_CODE (XEXP (x, 0)) == SUBREG