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Re: cprop_reg problem on sparc
From: Eric Botcazou <ebotcazou@adacore.com>
Date: Thu, 27 Oct 2011 23:11:33 +0200
>> Sorry, the final path component should be "mzero2.c"
>
> Thanks. I think we that need the same treatment in:
...
> as:
...
> i.e. we need to bail out if we are narrowing and this is a big-endian target.
I quickly tried the patch below, but this does not prevent the
transformation.
diff --git a/gcc/regcprop.c b/gcc/regcprop.c
index ad92a64..54e008b 100644
--- a/gcc/regcprop.c
+++ b/gcc/regcprop.c
@@ -448,6 +448,14 @@ find_oldest_value_reg (enum reg_class cl, rtx reg, struct value_data *vd)
if (hard_regno_nregs[regno][mode]
> hard_regno_nregs[regno][vd->e[regno].mode])
return NULL_RTX;
+
+ /* 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))
+ return NULL_RTX;
}
for (i = vd->e[regno].oldest_regno; i != regno; i = vd->e[i].next_regno)