Fix illegal register substitutions on big-endian during cprop_reg.

* regcprop.c (copyprop_hardreg_forward_1): Reject the transformation when we narrow the mode on big endian. From-SVN: r180600

Fix illegal register substitutions on big-endian during cprop_reg.
* regcprop.c (copyprop_hardreg_forward_1): Reject the transformation when we narrow the mode on big endian. From-SVN: r180600
26689420 · David S. Miller · David S. Miller · 53b51666 · 26689420 · 26689420
Commit 26689420 authored Oct 28, 2011 by David S. Miller Committed by David S. Miller Oct 27, 2011
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gcc/regcprop.c
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--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
+2011-10-27  David S. Miller  <davem@davemloft.net>
+
+	* regcprop.c (copyprop_hardreg_forward_1): Reject the
+	transformation when we narrow the mode on big endian.
+
 2011-10-27  Jakub Jelinek  <jakub@redhat.com>

 	* config/i386/sse.md (avx_cvtpd2dq256_2, avx_cvttpd2dq256_2,
--- a/gcc/regcprop.c
+++ b/gcc/regcprop.c
@@ -824,6 +824,14 @@ copyprop_hardreg_forward_1 (basic_block bb, struct value_data *vd)
 	      if (hard_regno_nregs[regno][mode]
 		  > hard_regno_nregs[regno][vd->e[regno].mode])
 		goto no_move_special_case;
+
+	      /* And likewise, if we are narrowing on big endian the transformation
+		 is also invalid.  */
+	      if (hard_regno_nregs[regno][mode]
+		  < hard_regno_nregs[regno][vd->e[regno].mode]
+		  && (GET_MODE_SIZE (vd->e[regno].mode) > UNITS_PER_WORD
+		      ? WORDS_BIG_ENDIAN : BYTES_BIG_ENDIAN))
+		goto no_move_special_case;
 	    }

 	  /* If the destination is also a register, try to find a source