patches/gcc/3.4.6/160-arm-ldm-peephole2.patch
author "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
Tue Sep 23 14:48:10 2008 +0000 (2008-09-23)
changeset 872 fd4bf138f08f
parent 746 b150d6f590fc
permissions -rw-r--r--
Bart De VOS pointed out that removing absolute paths from the libc linker scripts is plainly wrong.
It dates from dawn ages of the original crosstool code, and is not well explained. At that time, binutils might not understand the sysroot stuff, and it was necessary to remove absolute paths in that case.

/trunk/scripts/build/libc/glibc.sh | 14 2 12 0 ++------------
1 file changed, 2 insertions(+), 12 deletions(-)
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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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     }