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re PR middle-end/20973 (kdelibs (khtml) miscompiled by reload)

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PR20973
        * reload.c (push_reload, find_dummy_reload): Check for uninitialized
        pseudos.

From-SVN: r98460
This commit is contained in:
Michael Matz 2005-04-20 14:30:38 +00:00 committed by Michael Matz
parent 71fc0c1676
commit 687b527d75
2 changed files with 23 additions and 2 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2005-04-20 Michael Matz <matz@suse.de>
PR20973
* reload.c (push_reload, find_dummy_reload): Check for uninitialized
pseudos.
2005-04-20 Kazu Hirata <kazu@cs.umass.edu>
* tree-ssa-phiopt.c: Fix comment typos.

19
gcc/reload.c
View File

@ -1520,7 +1520,7 @@ push_reload (rtx in, rtx out, rtx *inloc, rtx *outloc,
But if there is no spilling in this block, that is OK.
An explicitly used hard reg cannot be a spill reg. */
if (rld[i].reg_rtx == 0 && in != 0)
if (rld[i].reg_rtx == 0 && in != 0 && hard_regs_live_known)
{
rtx note;
int regno;
@ -1534,6 +1534,11 @@ push_reload (rtx in, rtx out, rtx *inloc, rtx *outloc,
&& REG_P (XEXP (note, 0))
&& (regno = REGNO (XEXP (note, 0))) < FIRST_PSEUDO_REGISTER
&& reg_mentioned_p (XEXP (note, 0), in)
/* Check that we don't use a hardreg for an uninitialized
pseudo. See also find_dummy_reload(). */
&& (ORIGINAL_REGNO (XEXP (note, 0)) < FIRST_PSEUDO_REGISTER
|| ! bitmap_bit_p (ENTRY_BLOCK_PTR->global_live_at_end,
ORIGINAL_REGNO (XEXP (note, 0))))
&& ! refers_to_regno_for_reload_p (regno,
(regno
+ hard_regno_nregs[regno]
@ -1997,7 +2002,17 @@ find_dummy_reload (rtx real_in, rtx real_out, rtx *inloc, rtx *outloc,
is a subreg, and in that case, out
has a real mode. */
(GET_MODE (out) != VOIDmode
? GET_MODE (out) : outmode)))
? GET_MODE (out) : outmode))
/* But only do all this if we can be sure, that this input
operand doesn't correspond with an uninitialized pseudoreg.
global can assign some hardreg to it, which is the same as
a different pseudo also currently live (as it can ignore the
conflict). So we never must introduce writes to such hardregs,
as they would clobber the other live pseudo using the same.
See also PR20973. */
&& (ORIGINAL_REGNO (in) < FIRST_PSEUDO_REGISTER
|| ! bitmap_bit_p (ENTRY_BLOCK_PTR->global_live_at_end,
ORIGINAL_REGNO (in))))
{
unsigned int regno = REGNO (in) + in_offset;
unsigned int nwords = hard_regno_nregs[regno][inmode];