patches/gcc/3.4.6/601-gcc34-arm-ldm-peephole2.patch
author "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
Sun Feb 17 22:12:59 2008 +0000 (2008-02-17)
changeset 433 9886aa0a9694
permissions -rw-r--r--
Robert P. J. DAY says:

According to Mike Frysinger, this patch was removed from Gentoo in the
2.3.x series and didn't seem to cause any adverse effects. So toss it
from the patch directories for glibc 2.5 and up.
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diff -durN gcc-3.4.6.orig/gcc/config/arm/arm.c gcc-3.4.6/gcc/config/arm/arm.c
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--- gcc-3.4.6.orig/gcc/config/arm/arm.c	2007-08-15 22:57:51.000000000 +0200
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+++ gcc-3.4.6/gcc/config/arm/arm.c	2007-08-15 22:57:51.000000000 +0200
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@@ -4572,6 +4572,10 @@
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 int
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 adjacent_mem_locations (rtx a, rtx b)
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 {
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+  /* We don't guarantee to preserve the order of these memory refs.  */
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+  if (volatile_refs_p (a) || volatile_refs_p (b))
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+    return 0;
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+
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   if ((GET_CODE (XEXP (a, 0)) == REG
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        || (GET_CODE (XEXP (a, 0)) == PLUS
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 	   && GET_CODE (XEXP (XEXP (a, 0), 1)) == CONST_INT))
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@@ -4611,6 +4615,17 @@
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 	return 0;
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       val_diff = val1 - val0;
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+
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+      if (arm_ld_sched)
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+	{
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+	  /* If the target has load delay slots, then there's no benefit
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+	     to using an ldm instruction unless the offset is zero and
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+	     we are optimizing for size.  */
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+	  return (optimize_size && (REGNO (reg0) == REGNO (reg1))
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+		  && (val0 == 0 || val1 == 0 || val0 == 4 || val1 == 4)
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+		  && (val_diff == 4 || val_diff == -4));
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+	}
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+
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       return ((REGNO (reg0) == REGNO (reg1))
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 	      && (val_diff == 4 || val_diff == -4));
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     }