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re PR rtl-optimization/50448 (Missed optimization accessing struct component with integer address) 

PR rtl-optimization/50448
	* cprop.c (try_replace_reg): Also try to replace uses of FROM that
	appear in SET_DEST.

From-SVN: r181011
This commit is contained in:
Georg-Johann Lay 2011-11-05 13:08:54 +00:00 committed by Georg-Johann Lay
parent 69e596afa4
commit 8eee318f0a
2 changed files with 20 additions and 2 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2011-11-05 Georg-Johann Lay <avr@gjlay.de>
PR rtl-optimization/50448
* cprop.c (try_replace_reg): Also try to replace uses of FROM that
appear in SET_DEST.
2011-11-05 Peter Dufault <dufault@hda.com>,
Sebastian Huber <sebastian.huber@embedded-brains.de>

16
gcc/cprop.c
View File

@ -712,8 +712,8 @@ find_used_regs (rtx *xptr, void *data ATTRIBUTE_UNUSED)
}
}
/* Try to replace all non-SET_DEST occurrences of FROM in INSN with TO.
Returns nonzero is successful. */
/* Try to replace all uses of FROM in INSN with TO.
Return nonzero if successful. */
static int
try_replace_reg (rtx from, rtx to, rtx insn)
@ -764,6 +764,18 @@ try_replace_reg (rtx from, rtx to, rtx insn)
note = set_unique_reg_note (insn, REG_EQUAL, copy_rtx (src));
}
if (set && MEM_P (SET_DEST (set)) && reg_mentioned_p (from, SET_DEST (set)))
{
/* Registers can also appear as uses in SET_DEST if it is a MEM.
We could perhaps try this for multiple SETs, but it probably
won't buy us anything. */
rtx dest = simplify_replace_rtx (SET_DEST (set), from, to);
if (!rtx_equal_p (dest, SET_DEST (set))
&& validate_change (insn, &SET_DEST (set), dest, 0))
success = 1;
}
/* REG_EQUAL may get simplified into register.
We don't allow that. Remove that note. This code ought
not to happen, because previous code ought to synthesize