patches/gcc/3.4.6/601-gcc34-arm-ldm-peephole2.patch
author "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
Sun Feb 17 22:08:06 2008 +0000 (2008-02-17)
changeset 431 8bde4c6ea47a
permissions -rw-r--r--
Robert P. J. DAY says:

apparently, the patchset for gcc 4.2.1 applies properly to the
source for gcc 4.2.2 and gcc 4.2.3. so, if you want, you can simply
add support for those last two just by augmenting menuconfig and
adding a couple symlinks for those two directories. seems like a
cheap way to add a couple new versions.
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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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     }