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reload.c (find_dummy_reload): Don't use OUT as a reload reg for IN if it overlaps a fixed register.

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* reload.c (find_dummy_reload): Don't use OUT as a reload reg
	for IN if it overlaps a fixed register.

From-SVN: r191305
This commit is contained in:
Richard Earnshaw 2012-09-14 17:02:04 +00:00 committed by Richard Earnshaw
parent a27d595da2
commit 57132d23fa
2 changed files with 13 additions and 2 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2012-09-14 Richard Earnshaw <rearnsha@arm.com>
* reload.c (find_dummy_reload): Don't use OUT as a reload reg
for IN if it overlaps a fixed register.
2012-09-14 Eric Botcazou <ebotcazou@adacore.com>
PR rtl-optimization/44194

10
gcc/reload.c
View File

@ -2036,7 +2036,12 @@ find_dummy_reload (rtx real_in, rtx real_out, rtx *inloc, rtx *outloc,
However, we only ignore IN in its role as this reload.
If the insn uses IN elsewhere and it contains OUT,
that counts. We can't be sure it's the "same" operand
so it might not go through this reload. */
so it might not go through this reload.
We also need to avoid using OUT if it, or part of it, is a
fixed register. Modifying such registers, even transiently,
may have undefined effects on the machine, such as modifying
the stack pointer. */
saved_rtx = *inloc;
*inloc = const0_rtx;
@ -2049,7 +2054,8 @@ find_dummy_reload (rtx real_in, rtx real_out, rtx *inloc, rtx *outloc,
for (i = 0; i < nwords; i++)
if (! TEST_HARD_REG_BIT (reg_class_contents[(int) rclass],
regno + i))
regno + i)
|| fixed_regs[regno + i])
break;
if (i == nwords)